American Weasels

A suggestion that weasels sometimes obtain the prey killed by hawks is offered by Criddle and Criddle (1925:147) who write: "Hawks are not always the aggressors, as is shown by an incident reported by Mr. H. L. Seamans, of Lethbridge, Alberta. Mr. Seamans noted a large buzzard suddenly fly straight upwards from a fence post, and then alight upon another one some distance away. A little while afterward this bird once more arose in the same manner as before, and presently repeated the performance again. An investigation then followed and revealed that a Long-tailed Weasel was following the hawk from post to post.

"We should hardly expect a weasel to attempt to capture a bird of the above type. On the other hand, it is possible that these animals might be able to startle a hawk sufficiently to cause it to drop its prey, which would thus provide food for the weasel."

The following frequency index is compiled from the foregoing data on prey of Mustela frenata.

More significant than the above compilation, of course, are the results of careful studies of the food of the long-tailed weasel in restricted areas. Examples of such studies are those of Polderboer, Kuhn and Hendrickson (1941) and Hamilton (1933:333).

According to Hamilton's (1933:332) observations on captive weasels, "There seems to be little relative difference in the amount they eat, regardless of their activities.

"In general, more food is taken in summer than in winter. Usually about a third their weight every 24 hours is eaten, but a growing young weasel will consume much more. A young male noveboracensis, weighing 145 grams, consumed an entire chipmunk, fur and bones, weighing 85 grams, in 24 hours. A day later it ate all of a partly grown rat, 105 grams, in the same length of time."

Moore (1945:253) records that a captive male that he obtained at Gainesville, Florida, consumed, on the average, between 63 and 70 grams of flesh and blood per day. The weasel itself weighed approximately 320 grams.

Sanderson (1949:413), concerning seven young weasels from Manitoba, that he raised in captivity, writes: "From the fifth to the seventh week of age, they consumed approximately 22 per cent of their body weight per day; from the eighth to the tenth week (just before reaching mature size) they consumed approximately 24 per cent; but after reaching maturity they consumed only 18 per cent. When given all the food they would take in one day, they ate as much as 40 per cent of their body weight."

Criddle and Criddle (1925:143, 146) say that weasels drinking at a bird trough "held their mouths very close to the water and as far as we could see, lapped the liquid up with rapid movements of the tongue. As a rule, after drinking, they would merely spring to the ground and vanish amid a bunch of scolding birds, but occasionally we have seen an animal slowly drag itself through the water and follow this performance by some rapid gambols, or a quick run, a method of drying which most of us have practiced in our youth." According to Hamilton's (1933:332) observations on captives, "Weasels are great drinkers, and while they take but little at a time, about 25 c.c. is drunk by a large animal during a day. . . ."

Reproduction

Philip L. Wright's several papers (1942A, 1942B, 1947, 1948A, and 1948B) reporting on his detailed studies of Mustela frenata (subspecies oribasus and longicauda) in captivity have yielded a large share of the precise information that we have concerning breeding and reproduction in this species. He has found that a single litter, of up to 9 young is born in the spring, usually in April. At three months of age the females "are full grown." The young males remain sexually immature during the first summer but the young females, as well as the females which are more than a year old, come into heat in the midsummer and are bred by the adult males. After a long period of quiescence lasting for several months, the embryos resulting from these matings become active in early spring and develop to full term in less than 27 days after they become implanted. The adult males are sexually active from April into August, when the testes are at maximal size and are conspicuous in the scrotum. A gradual regression takes place starting in August and extending into September. By October the testes may be fully regressed and the molt to white may start in this month. The white winter weasel, of either sex, is sexually inactive. The testes of the sexually active male in early spring and late summer are seven to eight times the size of the fully regressed testes. Females which had borne and suckled young were first found to be in oestrus 65 to 104 days after birth of the young. Lactation lasts for approximately 5 weeks. In 18 litters the length of the gestation period varied from 220 to 337 days with an average of 279 days. The female in heat has the vulva much swollen and she will remain in this condition for several weeks if not bred. Wright (1948A) describes the actual mating as beginning with a scuffle after which the male grabs the female by the scruff of the neck with his teeth and holds her until she becomes subdued when he clasps her lower abdomen with his front feet and arches his back over her posterior regions. The two animals remain locked in this position usually for two hours and sometimes for longer than three hours. If the animals are left together, copulation may take place again on the same day or upon succeeding days.

Hamilton (1933:316-321) writes of a freshly born M. f. noveboracensis that it ". . . was pink and much wrinkled. The wetness . . . did not entirely obscure a few sparse, rather long, white hairs . . . over its back and head. It had the pronounced and extraordinarily long neck of the adult." At one day of age the average weight of six individuals in the litter was 3.1 grams, which is 3 per cent of the weight of the adult female and 1-1/2 per cent of the weight of an adult male. At two weeks of age "The silky white hair . . . obscures the general flesh color of the skin, evident a week earlier. The hair on the back of the head and neck, also over the shoulders, is slightly longer than that of the back . . ." but there is no crest or mane or pompadour at this or any other age such as characterizes the juvenal ermine. When 21 days old one young male "hurried from the nest chamber and commenced to eat some meat." At three and a half weeks "They are all eating small pieces of meat. . . . The canine teeth have made their appearance in both the upper and lower jaw, but just a hint of the incisors show. Some of the cheek teeth are through, as the meat appears to be thoroughly masticated by the little ones." On the 36th and 37th days the eyes opened. Sanderson (1949:415) found that a litter of seven young of Mustela frenata longicauda, from Manitoba, raised in captivity, "reached the peak of their growth" at approximately ten weeks of age.

Several nests have been found. In Manitoba, Sanderson (1949:412) excavated a burrow at the mouth of which he had trapped the adult female and in which he found eight young approximately five weeks old. The "burrow was about three inches in diameter, with two chambers at a depth of twelve inches. One of these was empty, the other contained the young. The two surface-openings were but two feet apart and the entire burrow was no more than three feet long. . . . The meager nest material consisted entirely of finely chopped grass. There was no mouse hair present, no accumulation of fecal material, and no storehouse containing food."

Charles O. Handley has written me that on January 25, 1929, on the Sinkola Plantation, Thomas County, Georgia, he investigated the living quarters of a family of five weasels, four of which had been shot five days before by a hunter. According to the hunter each of the four which had been killed was approximately two-thirds the size of one which escaped into a hole in the ground. Handley found that the weasels had been using as headquarters a burrow in the trunk of an old uprooted oak as well as a nearby gopher burrow. The burrow in the oak was approximately ten feet long and had been excavated in the rotten wood. In a distance of fifty feet along the gopher tunnel there were several used openings with pathways leading away from each. On February 6, Handley, with the help of a friend, trapped a large male weasel near this place.

Criddle and Criddle (1925:143) describe a female which, one winter, slept in a bag of feathers in a basement of a house occupied by one of the authors; another weasel in winter made its headquarters in a threshing machine. The nest of the latter "was somewhat roughly constructed and consisted of a convenient bunch of straw and chaff under the cylinder."

Harper (1927:303) in the Okefinokee Swamp of Georgia dislodged a weasel from the house of a wood rat and was told of a den found in the swamp "in the trunk of a hollow cypress tree" from which a mother weasel and three young "about the size of mice" were obtained. "The bed contained, I suppose, a bushel or more of rabbit hair, rat hair, and squirrel hair. It looked like it must have been used as a den for several years, although there was no stink that I could detect except the musk from the old Weasel." Another female and three young approximately half grown were found in a hollow pine log.

Between January 6 and April 12, 1940, on 640 acres of land, in Washtenaw County, Michigan, four weasels were studied and each weasel used only one den in this period (Quick, 1944:78). Criddle (1930:279) remarks that M. f. longicauda at Aweme, Manitoba, often makes its temporary headquarters in the burrows of pocket gophers (Thomomys). A female and three young weasels were found by Shaw (1921:167) using a nest of a mountain beaver in the burrow of that animal. Green (1936), in May, in Gratiot County, Michigan, saw a weasel enter a hole under a decayed log and investigated finding four young weasels in a nest mostly of Microtus fur.

In the early part (winter and spring) of 1939, at Ames, Iowa, Polderboer, Kuhn and Hendrickson (1941) studied four weasels living in four separate dens on 160 acres typical of Iowa farmland and excavated three of the dens. One den was in a weed patch in an old mole run. The nest chamber, approximately nine inches in diameter and six inches below the surface of the ground "was filled with grasses packed in a layer-like formation. In the center of this mass was a nest hollow lined with patches of mouse and shrew fur. Beneath this layer of fur and at the sides of the nest were skins, various bones, and skulls of partially eaten mice and shrews . . . scats [were in the nest]. . . . At intervals, layers of clean grass had been laid over the filth of the former bed, thus giving the nest a stratified appearance." A second den, of a large male, was in a field of sweet clover two feet high in the former burrow of a Franklin's ground squirrel. The nest cell, seven inches in diameter and nine inches below the surface of the ground, "was lined with grasses mixed with much rabbit and mouse fur. Some scats, and bones and fur of mice and shrews were matted together in layers at the bottom of the nest." When this den was abandoned the male weasel occupied, for a month, another burrow, 20 rods distant, of a Franklin ground squirrel, in the field of sweet clover. The nest cell measured 11 by nine inches and was 11 inches below the surface of the ground. "Two nest layers were present. The first, composed chiefly of coarse straw and grass, had apparently been occupied at some time by a spotted skunk. . . . On top of the skunk nest was the weasel nest composed of fine grasses, mouse fur, and skeletal remains of mice."

Relation of the Sexes to each other and to the young

Quick (1944:75) writes that on March 28, in Michigan, he found the tracks of a male and those of a smaller animal, supposedly a female, meeting. The two "then led along the fence for about 18 chains and both entered the den of the male. . . . Only the tracks of the smaller weasel left the den on the same date. Observation on April 12 showed that the large male still occupied the den." I am at a loss to explain this behavior since breeding would not be expected to occur in late March and since I suppose that the male and female do not live together except in the breeding season. Consequently, I wonder if the sign was wrongly read.

Hamilton (1933:328), however, writes that M. f. noveboracensis is to "be found in pairs when caring for the young. During mid-May, 1927, I several times saw a male of this species carrying food to a den of young ones." Green (1936), in May in Gratiot County, Michigan, remarks that while he was uncovering and examining a nest of four young weasels, two adults ran about excitedly and one removed a young weasel. In instances where several nearly full-grown young have been obtained from one den it has been my experience (Hall, 1946:191) that the only adult trapped there was the female; no adult male was found or in the one instance when found he was living alone in a den 200 yards away from the den of the female and her young. Data are too few to warrant a definite conclusion about the extent to which the male aids in rearing the young, but I have wondered if he might not do so when the young were less than half grown and then live alone when they were more than half grown.

Mustela frenata noveboracensis (Emmons)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

Putorius Noveboracensis Emmons, Quadrupeds of Massachusetts, p. 45, 1840.

Mustela fusca DeKay, Zool. of New York, Pt. 1, Mammalia, p. 34, 1842.

Putorius fuscus Audubon and Bachman, Journ. Acad. Nat. Sci. Philadelphia, 8 (Pt. 2):288, 1842; Audubon and Bachman, Vivip. quadrupeds of N. Amer., 3:234, pl. 148, 1853 (pl. 1848).

Putorius noveboracensis, DeKay, Zool. of New York, Pt. 1, Mammalia, p. 34, 1842; Baird, Mamm. N. Amer., p. 166, 1858; Merriam, N. Amer. Fauna, 11:16, pl. 4, figs. 1, 1a, 2, 2a, pl. 5, figs. 3, 3a, text figs. 4-6, 30, June 30, 1896; Bangs, Proc. Biol. Soc. Washington, 10:13, pl. 1, figs. 2, 2a, pl. 2, figs. 2, 2a, and pl. 3, figs. 3, 3a, February 25, 1896; Cory, Mamm. Illinois and Wisconsin, p. 366, plates, 1912.

Putorius erminea, Audubon and Bachman, Vivip. quadrupeds of N. Amer., 2:56, pl. 59, 1851.

Putorius agilis Audubon and Bachman, Vivip. quadrupeds of N. Amer., 3:184, pl. 140, 1853.

Putorius richardsonii, Baird, Mamm. N. Amer., p. 164, 1858 (part).

Putorius (Gale) erminea, Coues, Fur-bearing animals, p. 109, 1877 (part).

Putorius noveboracensis notius Bangs, Proc. New England Zool. Club, 1:53, June 9, 1899. Type from Weaverville, Buncombe County, North Carolina.

Mustela noveboracensis noveboracensis, Miller, U. S. Nat. Mus. Bull., 79:97, December 12, 1912; Soper, Journ. Mamm., 4:251, November 1, 1923.

Mustela cicognanii, Henninger, Journ. Mamm., 2:239, November 29, 1921; Seton, Lives of game animals, 2:584, 1929 (part, Ohio); Hamilton, Amer. Midland Nat., 14:290, July, 1933 (part, Ohio); Lyon, Amer. Midland Nat., 17:109, January, 1936 (part, Ohio).

Mustela noveboracensis, Jackson, Journ. Mamm., 3:15, February 8, 1922.

Mustela frenata noveboracensis, Hall, Carnegie Instit. Washington Publ., 473:104, November 20, 1936; Hall, Amer. Midland Nat., 18:304, March, 1937.

Type.—Williamstown, Berkshire County, Massachusetts. Type specimen not known to be in existence.

Range.—Altitudinally, sea level to highest parts of mountains of eastern United States; Canadian Life-zone of Ontario and Quebec southward through eastern United States in Canadian, Transition and Upper Austral life-zones to and including upper edge of Lower Austral Life-zone in the Carolinas and northern parts of Georgia, Alabama, and Mississippi; westward from the Atlantic Coast to St. Croix and Mississippi rivers. See figure 29 on page 221.

Characters for ready recognition.—Differs: From M. f. olivacea, in males, by width of tympanic bulla which is less than rather than more than 8.5 mm., and in adult females by total length which is less than rather than more than 345 mm. and by mastoid breadth which is less than rather than more than distance between articular faces of exoccipital condyle and glenoid fossa; from M. f. occisor by a number of average differences including smaller size, relatively shorter tail and relatively narrower skull (see measurements); from M. f. spadix by least width of color of underparts amounting to less than 41 per cent of greatest width of color of upper parts, absence of color of underparts on ankles and feet, adults with hind foot less than 50 in males and 40 in females, orbitonasal length less than 15.5 in males and 13.5 in females, length of tooth-rows less than 18.0 in males and 15.7 in females, mastoid breadth less than 25.5 in males and 22.0 in females; from M. f. primulina in males by interorbital breadth averaging more than 24 per cent of basilar length, orbitonasal length averaging more than 34 per cent of basilar length or 64 per cent of mastoid breadth, tympanic bullae less inflated anteromedially, than posteromedially, and in females by orbitonasal length amounting to more than two-thirds of mastoid breadth, by zygomatic breadth averaging less than 21, and by anterolateral margin of tympanic bullae not projecting below squamosal; from M. f. arthuri in males, by zygomatic breadth more than distance between anterior palatine foramen and anterior margin of tympanic bulla and by convex dorsal outline of skull in longitudinal axis.

Description.—Size.—Male and Female:

The length of the hind foot averages more than the basal length in males whereas the reverse is true in females. The tail, relative to the length of the body, is longer in males than in females. The average differences in external measurements of the two sexes in Massachusetts, are: total length, 104; length of tail, 42; length of hind foot, 12.1. In Michigan, where the males are smaller, corresponding differences are only, 65, 33, and 11. Weight of 19 adult males from New York (Hamilton, 1933:294), 225 (196-267) grams and in 13 adult females, 102 (72-126) grams. Weights of 2 adults from Michigan are: ♂ 258; ♀ 101 grams.

Externals.—Longest facial vibrissae black, brown, or white (often all three colors in same specimen) and extending beyond ear; carpal vibrissae same color as underparts and extending to apical pad of fifth digit; hairiness of foot-soles as shown in figure 19.

Color.—Upper parts, in summer, Vandyke Brown or darker than tone 4 of Burnt Umber of Oberthür and Dauthenay, pl. 304. Sometimes approaching tone 2 of Warm Sepia of Oberthür and Dauthenay, pl. 305. Underparts, in summer, ranging from white through Napthalene Yellow (Peterboro, N. Y.), Pale Orange Yellow (eastern Mass.), near Primuline Yellow (unusual specimen from Leelanau Co., Mich.) to near (c) Deep Chrome (no. 19053, U. S. Nat. Mus., Roan Mts., N. C.) In winter, all white except tip of tail, or upper parts near (12" 1) Rood's Brown and tone 2 of Raw Umber of Oberthür and Dauthenay, pl. 301, with underparts white or sometimes tinged with yellowish. Tip of tail at all times black. Upper parts of uniform color except for occasional slight darkening of nose. Color of underparts extends distally on posterior sides of forelegs to foot and sometimes over upper sides of toes and on medial sides of hind limbs only to knees. Least width of color of underparts averaging, in a series of twenty-two males, mostly in full winter pelage, from Liberty Hill, Connecticut, 21 (11-40) per cent of greatest width of color of underparts. In eleven females from the same place, corresponding percentages are 20 (14-29). Black tip of tail in same series of males, most of which are in full winter pelage, 70 (60-75) mm. long; thus longer than hind foot and averaging 50 per cent of length of tail-vertebrae.

Skull and teeth.—Male (based on ten adults from Massachusetts): See measurements and plates 16-18; weight, 3.6 (3.3-4.4) grams; basilar length, 44.6 (43.3-46.0); zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth less than postpalatal length; postorbital breadth more or less than length of upper premolars and greater than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth more or less (usually more) than distance between foramen opticum and anterior margin of tympanic bulla; breadth of rostrum less than length of tympanic bulla; least width of palate less than length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 3 to 6 upper incisors; height of tympanic bulla more or less than distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer or shorter than rostrum; anterior margin of masseteric fossa behind or directly below posterior fourth of m1.

Female (based on five adults from Mass.): See measurements and plates 31-33; weight, 1.7 (1.2-2.1) grams; basilar length, 36.5 (35.2-38.1); zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth more or less than length of upper premolars and more than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate more or less (usually less) than greatest length of P4; tympanic bulla as far posterior to foramen ovale as width of 4 to 5-1/2 upper incisors; height of tympanic bulla less than distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer than rostrum.

The skull of the female averages 53 per cent lighter than that of the average male.

Comparisons of the skull with those of M. f. olivacea, M. f. spadix, M. f. primulina, and M. f. arthuri, are made in the accounts of those subspecies. As compared with that of M. f. occisor the skull of adult male noveboracensis, is of smaller average size with relatively (to basilar length of Hensel) lesser mastoid and zygomatic breadths. In addition to the zygomatic arches of noveboracensis being less widely bowed outward they seem to be more rounded posteriorly. Comparisons of subadult females indicate that these differences exist in the females as well as in the adult males.

Remarks.—The earliest of the post-Linnaean references to this weasel mostly were under the specific name erminea in the belief that the American animal was the same as the larger of the two common species of weasel in the Old World. The name noveboracensis, now in use for this subspecies, was applied in 1840 and since that time the males usually have borne that name; the females, because they are smaller, were more frequently confused with some other species. Audubon and Bachman in 1853 even proposed the name agilis for the female in the mistaken belief that it was a species distinct from the male. After 1896, when Bangs correctly classified the weasels of the eastern United States, the males have been correctly identified and the females, except by a few authors, likewise have been correctly named. Because many early American naturalists did their first collecting of mammals in the geographic range of noveboracensis, the person who examines labels of specimens of this subspecies can find data written in the hand of Spencer Fullerton Baird, Theodore Roosevelt, and other naturalists famous for their work as scientists or accomplishments otherwise. The material is more nearly adequate than is that of many other subspecies and the number of specimens is exceeded—and only slightly—by that of the subspecies nevadensis, which like noveboracensis has a relatively large geographic range.

Intergradation with Mustela frenata spadix is indicated by subadult males from western Wisconsin, namely, one from Gordon, three from Colfax and one from Meridean. Linear measurements of the teeth of these specimens are exactly intermediate between those of spadix from Elk River, Minnesota, to the west, and noveboracensis from, say, Beaver Dam, Wisconsin, to the east. The specimens from western Wisconsin show approach to spadix also in that the length of the tooth-rows and breadth of the rostrum are slightly greater than in noveboracensis from farther east, say, Beaver Dam, Wisconsin.

Indeed, animals from as far east as Beaver Dam itself might be thought of as showing some approach to spadix. Although, along the eastern seaboard, the upper lips, with rare exceptions, are the same color as the underparts, farther west, in Michigan and Wisconsin, the lips more often than not are white. Animals from Beaver Dam have slightly shorter black tips on the tails, broader extent of the light color of the underparts and females average slightly larger than typical noveboracensis, say, those from Massachusetts. Each of these differences reflects characters found better developed in the spadix-longicauda stock to the west.

Toward the southern part of its range where noveboracensis meets M. f. olivacea there is a marked increase in yellowness of the underparts. This coloration of the underparts, since it is not so well marked in the northern part of the range of noveboracensis, might be regarded as showing intergradation with olivacea and primulina, each of which has far more intensely colored underparts than does noveboracensis. Excepting this increase of yellow on the underparts, however, there are few if any characters of noveboracensis which undergo marked change as approach to the range of olivacea is made. Indeed, the characters of noveboracensis remain constant to within a relatively short distance of the geographic range of olivacea.

Notwithstanding the state of affairs described above, intergradation seems to take place. Three specimens referred to noveboracensis but which at the same time are regarded as intergrades with olivacea are as follows: No. 28.300, Charleston Museum, from five miles east of York, South Carolina, is an adult female with a badly crushed skull. In external measurements the specimen agrees with noveboracensis. The underparts, as regards color and width, are intermediate. The general proportions of the skull and tympanic bullae agree with those of noveboracensis but the skull is larger than in any female of true noveboracensis and approaches that of olivacea. The same can be said of a young female, no. 80, Ohio State Museum, from Roswell, Georgia.

Another female, no. 171559, U. S. Nat. Mus., from Lookout Mountain, 1500 ft., Fort Payne, Alabama, is barely subadult. The external measurements are nearer those of olivacea. The color and narrowness of the underparts are typical of noveboracensis. The proportions and especially size of the skull show approach to olivacea, though they are nearer to noveboracensis when all features are taken into account. In the northern part of its range individuals of noveboracensis attain larger size than farther south. This tendency reaches its extreme, in males at least, in M. f. occisor of Maine. Specimens of noveboracensis from the Adirondacks of New York average larger (see cranial measurements on page 418) than those from farther south, and thus approach occisor in size as well as in geographic position. Also, occasional individuals which strongly show characters of occisor are found even farther south than the Adirondacks of New York. This is true of no. 96518, U. S. Nat. Mus., ♂ ad., from Lunenburg; Massachusetts. The animal has a large skull of relatively great width much as in occisor, although its external measurements, relative length of tail and long, terminal, black brush place it with noveboracensis rather than with occisor. Of a pair of specimens from Ossipee, New Hampshire, the male, no. 77108, U. S. Nat. Mus., has a long (175 mm.) tail, and short (60 mm.) black pencil as in occisor, although otherwise it is referable to noveboracensis. Still another specimen, a subadult male, no. 4193, Mus. Comp. Zoöl., from Upton, Maine, has a longer (51 mm.) hind foot than noveboracensis although it otherwise agrees with that subspecies. As remarked by Bangs (1899:55), other than fully adult specimens from the range of occisor are "troublesome," and would not be selected as distinct from noveboracensis if placed in a series of that subspecies, say, from New York State. In view of the facts that several specimens from intermediate localities combine the characters of noveboracensis and occisor, that noveboracensis in the northern part of its range averages larger than it does farther south and thus approaches occisor in size, and that occasional large specimens resembling occisor in several, but not all, features sometimes crop up in the northern part of the range of noveboracensis, it appears that noveboracensis and occisor intergrade. Therefore they are treated as two subspecies of the single species, Mustela frenata.

Intergradation with M. f. primulina has been commented on in the discussion of that subspecies. Female, no. 159980, U. S. Nat. Mus., from Golconda, Illinois, has many characters of primulina but two young males from there agree better with noveboracensis.

Examination of 283 adult and subadult skulls for malformation of the frontal sinuses revealed only ten that were not obviously malformed. Two were from New York, one from Massachusetts, one from Pennsylvania, and six from the 52 specimens from Michigan and Wisconsin. In addition, skulls of many young and even juveniles were malformed.

Specimens examined.—Total number, 555, arranged alphabetically by states and provinces and, unless otherwise noted, from north to south by counties in each state. Except as otherwise noted specimens are in the United States National Museum.

Alabama. DeKalb County: Fort Payne, 1.

Connecticut. Litchfield County: Riverton, 1[5]; Gaylordsville, 1. Hartford County: East Hartford, 4 (3[5]); Glastonbury, 2[5]; South Glastonbury, 4[5]. Windham County: Plainfield, 2 (1[14]). Fairfield County: Greenwich, 2[2]. New London County: Liberty Hill, 35 (33[75], 2[7]).

District of Columbia. Washington, 3; near Washington, 1; Eastern Branch, 1; Congress Heights, 1; Benning, 1; no definite locality, 1.

Georgia. Towns County: Young Harris, 1. Cherokee County: Canton, 1. Cobb County: Roswell, 1[81].

Indiana. St. Joseph County: Notre Dame, 2[99]. Porter County: Hebron, 1. Miami County: Denver, 5 (4[75], 1[4]). Wells County: Bluffton, 1. Howard County: Russiaville, 1. Jay County: Salamonia, 1[2]. Boone County, 1[2]. Knox County: Bicknell, 3.

Illinois. Lake County: Camp Logan, 3[60]; Fort Sheridan, 1[60]. Cook County: W Northfield, 2; Flossmoor, 1[60]; no locality more definite than county, 1. Du Page County: Bloomingdale Spg., 1[60]. Carroll County: Savanna, 1[87]. McLean County: Normal, 1[7]. Champaign County: Harwood Township, 1[7]. Pike County?: Milton Spring, 1[60]. Pope County: Golconda, 3.

Kentucky. Woodford County: Midway, 1. Hancock County: Hawesville, 1.

Maine. Oxford County: Upton, 1[75]; Bethel, 1[74].

Maryland. Howard County: Long Corner, 1; Hanover, 1. Montgomery County: Gaithersburg, 1; Garret Park, 1; Chevy Chase, 1; Bethesda, 1. Prince Georges County: Laurel, 18; Plummer Island, 3; Oxon Hill, 1. Talbot County: Easton, 1. Dorchester County: Cambridge, 5[40].

Massachusetts. Middlesex County: Wilmington, 6; Burlington, 6; Lexington, 1[75]; Wayland, 2[75]. Berkshire County: New Marlboro, 1[5]. Worcester County: Lunenburg, 2; Lancaster, 1[75]; Princeton, 2[75]. Norfolk County: So. Weymouth, 1[75]. Plymouth County: Wareham, 5[75].

Michigan. Marquette County: Michigamme, 1. Charlevoix County: Thumb Lake, 1[76]; 1/2 mi. N Thumb Lake, 1[76]. Leelanau County: Leland, 3[76]; Duck Lake, 2 mi. S Leland, 1[76]; Lost Pond, 8-1/2 mi. S Leland, 1[76]. Osceola County: Le Roy, 2[76]. Huron County: Rush Lake, 1[76]. Saginaw County: East Saginaw, 1. Oakland County: Royal Oak, 4[76]; South Lyon, 1[76]. Livingston County: Portage Lake, 1[76]. Washtenaw County: Portage Lake, 6[76]; Waterloo, 2[14]; Lima, 1[76]; Ann Arbor, 11[76]; 3 mi. E Ann Arbor, 1[76]; 2 mi. SE Ann Arbor, 1[76]; 2 mi. S Ann Arbor, 1[76]; 3 mi. S Ann Arbor, 1[76]; Dixboro, 1[76]; Pittsfield, 3 (2[76]); Saline, 1[76]; near Saline, 2[76]; 1 mi. S Saline, 2[76]; York, 2[76]; Manchester, 2[76]. Lenawee County: Morenci, 1[76]. Cass County: Marcellus Township, 1[76]. Berrien County: Harbert, 1[76]; Warren Wood Preserve, 1[76]; Warren Woods, 1[76].

New Hampshire. Grafton County: Franconia, 1[2]. Carroll County: South Chatham, 4 (3[5]); Ossipee, 2; Intervale, 1[5]. Merrimack County: Webster, 2[75].

New Jersey. Morris County: Morristown, 1. Essex County: West Orange, 1[2]. Mercer County: Princeton, 1[1]. Ocean County: Point Pleasant, 1[2]. Camden County: Haddonfield, 1[1]. Cumberland County: Millville, 2[74].

New York. St. Lawrence County: Ogdensburg, 1[74]. Clinton County: Rouses Point, 1[80]. County?: Adirondacks, 12. Essex County: Elizabethtown, 1; Schroon Lake, 1; no locality more definite than county, 1. Lewis? County: Locust Grove, 4; Lyons Falls, 1. Warren County: Lake George, 6; Caldwell, 1. Hamilton County: Beaver Brook, 1/2 mi. above mouth Indian Lake, 1[80]. Oswego County: Scriba, 2[74]; Palermo, 1[74]. Monroe County: Penfield, 3. Madison County: Peterboro, 6 (2[75]). Schoharie County: Schoharie, 1[2]. Rensselaer County: East Shodack, 1[80]. Tompkins County: Taughannock Falls, 2[58]; Ithaca, 4 (3[58]); Glenside, Ithaca, 1[58]; 6 mi. Creek, Ithaca, 1[58]. Green County: Lanesville, 1[2]. Orange County: Poplopen's Pond, 1[2]; Highland Falls, 1[2]. Putnam County, 1[19]. Westchester County: Sing Sing, 4; Armonk, 1[2]; Hastings, 3 (2[2], 1[19]). Nassau County: Flushing Meadows, 1[2]; Flushing, 1[58]; near Flushing, 1[2]; Oyster Bay, 2. Long Island: Cold Spring Harbor, 1; Bridgehampton, 1[2]. County in question: Severance, 3; Lake Grove (Long Island?), 1.

North Carolina (east to west by counties). Wake County: Raleigh, 4 (1[2], 1[75], 2[76]). Mitchell County: Magnetic City, foot of Roan Mountain, 6; Roan Mt., 1; Roan Mt., 6000 ft., 3. Buncombe County?: Valley of Black Mts., 1[2]. Madison County, 2[11].

Ohio. Trumbull County: Warren, 1[93]. Seneca County: Tiffin, 1[81]. Summit County: Ira, 2[81]. Crawford County: Galion, 1[81]. Ashland County: Loudonville, 1[76]. Auglaize County: New Bremen, 3[81]. Franklin County: 3 mi. N Columbus, 1[81]; Minerva Park, Columbus, 5[81]. Fairfield County: Sec. 32, Pleasant Twp., 1[81]; Lancaster, 1[81]. Clinton County: Reesville, 1; 1/2 mi. S and 1/2 mi. W Wilmington, 2[74]. Pike County: Waverly, 1[81].

Ontario. Sudbury District: Metagama, 2[86]. Carleton County: Ottawa, 2[77]. Muskoka County: Lake of Bays, 1; Bracebridge, 1. Haliburton County: Gooderham, 1[60]. Simcoe County: Orillia, 4 (2[2], 2[60].) Prince Edward County: Bloomfield, 1[77]. York County: Toronto, 1[2]. Waterloo County: Branchton, 3[60]; Preston, 2[77]; no locality save county, 1[60]. Welland County: Ridgway, 1[14]. Elgin County: St. Thomas, 1[77]. Essex County: Kingsville, 1[77]; Point Pelee, 1[77].

Pennsylvania (east to west by counties). Crawford County: Pymatuning Swamp, 3-1/2 mi. W Linesville, 1[9]; Meadville, 2[9]. Beaver County: Beaver, 1[9]; Raccoon Creek, 1[9]. Butler County: Mars, 1[9]; Leasuresville, 4[9]. Allegheny County: Allegheny, 1. Warren County: Bear Lake, 2[9]. Westmoreland County: Kingston, 1[9]; Laughlinstown, 2[9]. Somerset County: Confluence, 1[9]; Tub Mill Run, 2 mi. N Springs, 1[9]. Jefferson County: Siegel, 1[9]. Clearfield? County: Penfield, 1[9]. Cambria County: Cresson, 1[9]. Fulton County: Well's Tannery, 1[9]. Clinton County: near Round Island, 2[1]. Cumberland County: Carlisle, 1. Snyder County: 5 mi. S Selinsgrove, 1. Northumberland County: Pottsgrove, 1. Union County: Mifflinburg, 1. Sullivan County: Lopez, 7 (4[1], 3[74]). Chester County: Westtown, 1[1]; Valley Forge, 1[1]; W Bradford Township, 1[1]; no locality more definite than county, 3. Philadelphia County: Holmsburg, 2[1]. Bucks County: 1[1]. Pike County: Milford, 1.

Rhode Island. Providence County: Chepachet, 1. Washington County: Lake Warden, 2.

Quebec. Megantic County: Black Lake 1[77]. County in question: Meach Lake, 1[77].

South Carolina. York County: 5 mi. E York, 1[11]. Laurens County: Laurens, 1[39].

Tennessee. Campbell County: Highcliff, 1. Carter? County: Roan Mts., 1[2]. Hamilton County: Walden Ridge, near Soddy, 3.

Vermont. Windsor County: Hartland, 1[2].

Virginia. Shenandoah County: Toms Brook, 1. Arlington County: Arlington, 1; Ballston, 1; Alexandria, 1. Fairfax County: Falls Church, 3; Mt. Vernon, 2; no locality more definite than county, 1. Prince William County: Occoquan, 1. Essex County: Montague, 1. Prince George County, 1. Norfolk County: Wallaceton, 1. Grayson County: Mt Rogers, 3. County in question: Dismal Swamp, 1; Massanutten Mt., 1.

West Virginia. Hardy County, 1. Pendleton County: radius of 2 mi. Smoke Hole, 1[74]. Greenbriar County: White Sulphur, 2[60].

Wisconsin. Douglas County: Gordon, 1[102]. Vilas County: Mamie Lake, 4. Dunn County: Colfax, 4[102]; Meridean, 1[102]. Door County: state game farm, 17[102]; no locality more definite than county, 1[102]. Dodge County: Rolling Prairie, 1[50]; Beaver Dam, 52[50]. Dane County: Wingra Lake, 1[102]. Waukesha County: Pewaukee, 2[102]. Racine County: Waterford Township, 2[102]. Rock County: Milton, 1[102]; Bowers Lake, 1[102]. Walworth County: Lane's Mill, 8 mi. N Elkhorn, 7 (1[102], 6[54]); Delavan, 7.

Mustela frenata occisor (Bangs)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

Putorius occisor Bangs, Proc. New England Zool. Club, 1:54, June 9, 1899.

Mustela occisor, Miller, U. S. Nat. Mus. Bull., 79:98, December 31, 1912.

Mustela frenata occisor, Hall, Carnegie Instit. Washington Publ. 473:104, November 20, 1936.

Type.—Male, adult, skull and skin; no. 9102, coll. of E. A. and O. Bangs in Mus. Comp. Zoöl.; Bucksport, Hancock County, Maine; January 15, 1899; obtained by Alvah G. Door but measured and sexed by O. Bangs.

The skin is well made and in good condition. It is in full, white winter-dress with black-tipped tail. The skull has the posterior half of the left zygomatic arch broken away; otherwise the skull is unbroken and complete. Left I3 and right P3 are missing. The teeth otherwise all are present and entire.

Range.—Maine; possibly north locally to south side of St. Lawrence River in Quebec and possibly occurring in western New Brunswick. Zonal range Canadian and probably Transition. See figure 29 on page 221.

Characters for ready recognition.—Differs from M. f. noveboracensis by a number of average differences including larger size, relatively longer tail and relatively wider skull (see page 225, and measurements on pages 418, 419).

Description.—Size.—Male: Five adults yield average and extreme measurements as follows: Total length, 443 (430-465); length of tail, 163 (154-175); length of hind foot, 50 (47-54). Tail averages 58 per cent as long as head and body. Length of hind foot averages more than basal length.

Female: Measurements of two subadult female topotypes are as follows: Total length, 346, 318; length of tail, 116, 110; length of hind foot, 39, 35.5.

Tail amounts to 50 per cent and 54 per cent of body-length respectively. Length of hind foot more or less than (about equal to) basal length.

The average differences in external measurements of the two sexes are: Total length, 111; length of tail, 50; length of hind foot, 12.5.

Externals.—As described in Mustela frenata noveboracensis.

Color.—As described in Mustela frenata noveboracensis except that black tail-tip in series of 10 males in full winter pelage 60 (45-80) mm. long; thus averaging 39 per cent of length of tail vertebrae.

Skull and teeth.—Male (based on 3 adults): See measurements and plates 16-18. As described in Mustela frenata noveboracensis except that: Weight, 4.2 (4.1-4.3) grams; basilar length, 45.7 (44.9-46.9); zygomatic breadth more or less than (about equal to) distance between anterior palatine foramen and anterior margin of tympanic bulla; least width of palate rarely less than length of P4; anterior margin of masseteric fossa behind or directly below posterior half of m2.

Female (based on 2 subadults): See measurements and plates 31-33. As described in Mustela frenata noveboracensis except that: Weight, 2.0 (1.9-2.1) grams; basilar length, 37.3, 38.2.

Comparison of the skull with that of M. f. noveboracensis is made in the account of that subspecies.

Remarks.—Excepting a specimen in the Academy of Natural Sciences of Philadelphia, obtained in 1893, and two in the Boston Society of Natural History, obtained in 1925, I have seen no material of this subspecies in addition to that examined by Bangs at the time he prepared the original description in 1899.

Anderson (1945:56, 57) records a specimen, Canadian National Museum Catalogue Number 18426, from Kamouraska County, Quebec, as of this subspecies and thinks that occisor occurs north of Maine "locally to south side of lower St. Lawrence River in Quebec; probably also in western New Brunswick."

So far as the available material of occisor permits one to judge, it is distinguished from noveboracensis by a combination of characters no one of which invariably can be relied upon as diagnostic. Employing adult males, average differences indicate that M. f. occisor is larger in each of the external and cranial measurements; tail relatively longer; black tip of tail relatively shorter; mastoid and zygomatic breadth relatively greater and zygomatic arches more nearly square posteriorly.