The Project Gutenberg eBook of The Animal Parasites of Man, by H. B. Fantham, J. W. W. Stephens and F. V. Theobald.

The head louse lives especially in the hairy parts of the head of human beings; more rarely it is found on other hairy parts of the body. It is spread over the entire surface of the globe, and was present in America before the arrival of Europeans. Quite exceptionally it is said that it bores itself deep into the epidermis and can live in ulcers.

[The eggs are pear-shaped and are attached to the hairs near the roots by means of a clasping collar. They hatch in about seven days. The young are like the adults and mature in a month. Its general colour varies with that of its host. In West Africans nearly black, in Hindoos dark and smoky, on Chinese and Japanese yellow, on Hottentots orange, on South American Indians dark brown (Murray).—F. V. T.]

The head in front is somewhat rounded. Antennæ longer than in the head louse; 2 to 3·5 to 4 mm. in length; whitish-grey; the abdomen is broader than the thorax; stigmata as in P. capitis. Eggs 0·7 to 0·9 mm. in length; about seventy are deposited.

P. vestimenti lives on the neck, throat and trunk of persons, and the clothing next the body, in which also the eggs are deposited. The louse of so-called pedicular disease (P. tabescentium) is, according to Landois’ researches, only the usual P. vestimenti; moreover, many cases of phthiriasis are attributable to mites or fly maggots.

[This parasite has often been a great pest amongst soldiers during long campaigns, especially amongst the Russians during the Crimean War. Vide also notes in Addenda (p. 615) under “Body, Head and Clothes Lice.”—F. V. T.]

Male 0·8 to 1·0 mm. in length; female 1·12 mm. in length; colour greyish-white; form subquadrate; the two posterior pairs of legs are strong; the abdomen has nine segments and six pairs of stigmata; and still another pair of stigmata is situated between the two anterior limbs. Eggs pear-shaped, 0·8 to 0·9 mm. in length, 0·4 to 0·5 mm. in breadth, and are deposited in rows of about ten on the hairs.

The bed bugs live in the cracks and fissures of human habitations, under carpets, behind pictures, in furniture, bedsteads, etc.; hidden during the day, they attack persons at night to suck their blood. The alkaline secretion of the salivary glands dropped into the wound around the separate bites causes the so-called “wheals.”

The bed bugs were known in bygone days by the Greeks (κάριο) and the Romans (cimex). They were first mentioned from Strasburg in the eleventh century, and in England about 1500.

[This is the common bed bug of northern latitudes and must not be confused with the tropical bed bug (C. rotundatus). The bed bug can migrate from one house to another; this especially takes place when a house is uninhabited. They escape from windows and pass along walls, water-pipes and gutters, and so reach adjoining houses. This noxious pest accompanies man wherever he goes; ships and trains become infested, especially the former.

[A characteristic feature in this animal is the peculiar odour it produces, like many others in the same group of insects. This odour comes from a clear, oily volatile liquid secreted by glands in various parts of the body. Although the normal food is man’s blood, the bed bug can subsist upon moist wood, dust and dirt that collects in crevices in floors, walls, furniture, etc. The puncturing mouth consists of a fleshy under lip, within which lie four thread-like hard filaments which pierce the flesh, the blood being drawn up through the beak.

[The eggs are oval, white, with a projecting rim around one end, with a lid which is pushed off when the young hatch; they are laid in cracks and crevices in batches of from twelve to fifty. The egg stage lasts from seven to ten days. The larval stage so gradually passes into the adult that one scarcely notices the change; during its growth the skin is cast five times, and at the change the little wing-pads are seen, showing that the adult stage is reached. The young larva is at first pale yellowish-white. It resembles the parent, but has no trace of elytra. Although eleven weeks is said to be necessary for their development, the stages may be gone through much more rapidly; Howard and Marlatt 362 give seven weeks in some instances. It seems pretty certain that these Cimex only take one meal of blood between each moult and another preceding egg laying.—F. V. T.]

[This bug is common in warm climates; it is an abundant insect in India, and King has found it in the Sudan, where C. lectularius is, however, the common species. It is usually known as the tropical bed bug. Signoret’s bug can be told from the other common species by the shape of the pronotum. In C. rotundatus it is uniformly convex, whilst in C. lectularius the lateral edges are flat and sometimes even concave. The abdomen of rotundatus is also rather more elongate.

[This species is of considerable importance, as according to Patton it may act partly as the intermediary host of the piroplasma of kala-azar.

[Wenyon found at Bagdad that Cimex sp. would take up Leishmania from Oriental sore, and that the parasite developed into flagellate form. Patton came to the conclusion that the bed bug transmitted Oriental sore in Cambay, India, but Wenyon contests this view (vide Journ. Lond. School Trop. Med., 1912, ii, pt. 1, pp. 13–26). Franchini (Bull. Soc. Path, exot., 1912, v, No. 10, pp. 817–819) was unable to connect Cimex with this disease. At present nothing seems proved. Besides their possible connection with kala-azar, it has been shown by Howard and Clark (Journ. Exp. Med., 1912, xvi, No. 6, pp. 850–859) that they can carry the virus of poliomyelitis.

[This bed bug was originally described from the Island of Réunion in 1852 by Signoret. A similar insect was described from Burma by Fieber, in 1861, as C. macrocephalus. This is the same as Signoret’s species.

[The distribution given by Patton363 is as follows: India, Burma, Assam, Malay, Aden, Islands of Mauritius and Réunion. Patton in this paper refers to an erroneous statement made in a recent edition of this book (the last English edition). As I have personally kept lectularius in moist dirt, wood and refuse for over two years, the statement as far as I am concerned is not erroneous. Moreover, since his doubting this fact the same experiment has been twice repeated with the same results. What they did and do persist on I cannot say.—F. V. T.] whilst collecting them. It is rounder and has shorter antennæ than

[This is common in parts of Europe in pigeon nests, and also amongst poultry (vide Report Econ. Zool. for year ending September 30, 1913, pp. 142–144, Theobald). It occurs in Britain on the latter and will attack man. I have personally been badly bitten C. lectularius. Jenyns also described a more pubescent species from swallows as C. hirundinis. I have recently received an account of the swallow bug invading a house in Kent and causing much annoyance.—F. V. T.]

3·3 mm. in length, yellowish-red, thickly covered with hair; indigenous in Russia (Kasan).

Head long, narrowed behind into a neck; eyes large, prominent; rostrum thick and curved; antennæ moderately long, slender at the tip; legs long and stiff; carnivorous.

Amongst the Reduviidæ one genus is of particular importance, namely the genus Conorhinus, which has a long head and the first segment of the beak very much shorter than the second, and the posterior tibiæ longer than the femora.

These large bugs have a wide distribution, the Oriental region, North and South America, and the West Indies, Madagascar and West and Central Africa.

These large bugs may cause very nasty wounds by their bites, but beyond that it has recently been shown that one interposes in the life-cycle of a trypanosome, namely—

This large bug has recently been shown by Chagas to be the agent in the development of the trypanosome (T. cruzii) which is the cause of the well-known disease in many parts of Brazil called Barbeiro (Barbier). This insect is about 1 in. long, black, with four red spots on the pronotum, and six red lateral lines on the abdomen, black legs, head and beak. The insect is figured in a coloured plate (No. 9) in Mem. Inst. Oswaldo Cruz, 1909, i, fasc. 2, pp. 158–218.

This bug is also known as the Texas or Mexican bed bug, also as the big bed bug. It is particularly troublesome in the Mississippi Valley in bedrooms. The bite is very severe and results in more pronounced swelling and inflammation than that of the Cimex. Normally this genus feeds upon the blood of mammals and insects. Its fondness for human blood appears to be quite a new habit, and appears limited to the mature insect only. It is nearly an inch long, flat, head very narrow and long, the rostrum short and thick. In colour it is dark brown with pink markings. They are fully winged when adult, and they fly with ease, entering houses on the wing, especially being attracted by lights in windows; they also run swiftly. Like the bed bug they conceal themselves during the day and come out at night and bite the sleeper. The effect of the bite is very varied, but as a rule a sore, itching wound, accompanied by burning pain and swellings, which may extend over a good deal of the body, occur. A specific poison is undoubtedly injected into the puncture; but no doubt serious results are also due to the beak being contaminated through the insects feeding upon foul carrion. Mr. Lembert, when bitten by a Conorhinus sp. (?) on the Pacific slope, exhibited the following symptoms: an itching sensation extending up the leg, large blotches manifesting themselves on the upper part of the limb and extending up to the hands and arms; his lips swelled and the itching and swelling extended over the head; there was also much nausea. Similar results are recorded from other regions.365

The eggs of the C. sanguisuga are at first white, then become yellow, then pink; the young hatch in twenty days. There are two larval and two pupal stages, the latter showing wing-pads. The eggs are laid and the young feed out of doors, chiefly upon insects. It is particularly abundant in April and May indoors.

Another species; acts in a very similar way in California, the bite being very poisonous.

This large bug attacks man in Malaysia and elsewhere. It is recorded as inflicting “a very nasty sting, which is done by the huge proboscis.” Acute pain and inflammation follow in a few minutes. In one case the whole leg became swollen. This species occurs over the whole Oriental region, in Madagascar and Sierra Leone. It is dark brown in colour with dusky yellow or brick-red markings on the pronotum and elytra. Donovan suggests that it may be connected with the kala-azar piroplasma.

This large black bug is mentioned by Darwin,367 who states as follows: “At night I experienced an attack (for it deserves no less a name) of the benchuca, a species of Reduvius, the great black bug of the Pampas. It is most disgusting to feel soft wingless insects, about an inch long, crawling over one’s body. Before sucking they are quite thin, but afterwards they become round and bloated with blood, and in this state are easily crushed. One which I caught at Iquique (for they are found in Chili and Peru) was very empty. When placed on a table, and though surrounded by people, if a finger was presented the bold insect would immediately protrude its sucker, make a charge and, if allowed, draw blood. No pain was caused by the wound. It was curious to watch its body during the action of sucking, as in less than ten minutes it changed from being flat as a wafer to a globular form. This one feast, for which the benchuca was indebted to one of the officers, kept it fat during four whole months, but after the first fortnight it was quite ready to have another suck.” Mr. Kirby368 also refers to this species.

Occurs in Florida in houses, and chases bugs (Cimex) and flies; not definitely known to bite man.

This species occurs in South America. It is one of the forms known as bichuque. Its bite makes a troublesome swelling.

European, but also found in the United States. The bite causes intense pain. It bites when caught or handled, but does not seem to do so voluntarily. Swelling and irritation result which may last a week, and may even cause death.370 In 1899 it was very abundant at Washington and elsewhere; other species occurred, and so no definite opinion existed as to the actual biter, but some people took R. personatus actually biting. It was first described as a parasite of man in America by Walsh and Riley.371

A popular name for this bug is the wheel or masked bug—a black insect, three-fourths of an inch long. The larva of this bug is carnivorous and covers its body with dust so as to conceal itself from its prey. The adult is active on the wing.

Syn.: Nabicula subcoleoptrata, Kirby, 1837; Nabis subcoleoptratus, Reuter, 1872; Coriscus subcoleoptratus, Stål, 1873.

Northern United States. Howard was bitten by one between the fingers—the pain was intense, like a needle prick, but the swelling was small.372 No other case known.

Syn.: Pirates biguttatus, Stål, 1862; Callisphodrus biguttatus, Stål, 1866; Rasahus biguttatus, Stål, 1872.

Common in southern United States, and found in Cuba, Panama and Pará, etc. Known as the two-spotted corsair on account of the great spot on the hemielytra. Frequently found in houses, where it chases the bed bug. It also bites man frequently. From 1869 Walsh and Riley placed it amongst the parasites of man. In the United States Davidson373 is of opinion that all cases attributed to spider bites are due to this insect.

Syn.: Pirates morio, Erichson, 1848; Melanolestes morio, Stål, 1866; Pirates picipes, Herrich-Schäffer, 1848; Melanolestes picipes, Howard, 1900.

Guiana and Mexico and eastern and southern United States. Length 20 mm., hides under stones and logs during daylight, and flies at night. Attracted by lights into houses. Very abundant in 1899 at Washington. Howard cites cases where it was proved to bite man.

Syn.: Pirates abdominalis, Herrich-Schäffer; Melanolestes abdominalis, Uhler, 1875.

Allied to the former; some say similar, but can be told by the shorter wings on the female. It occurs in the same localities as M. morio.

Broad and very flat bugs, with antennæ of four segments and the beak of three; scutellum short, no cuneus to elytra and the tarsi of two segments. They normally live under the bark of trees, etc., and are found in most parts of the world.

A large species which is found in South America, frequenting houses, and bites very severely.

The bug is described by Wellman (Journ. Trop. Med., April 2, 1906, p. 97) as not only feeding on ticks, such as Ornithodorus moubata, but as also attacking man. It is called by the Angola Bantus the ochindundu. It is black in colour; the first two pairs of legs are of a bright red hue. It has curious paddle-like structures on the front four legs, which seem to be designed for securely holding the ticks. It infects native kraals for the sake of preying on ticks. The natives also state that it inflicts a bite which far exceeds in painfulness that of the tick. They compare the bite with that of a poisonous snake.

Scutellum short; antennæ four-jointed; ocelli present; membranous part of hemielytra with never more than five nervures. Nearly all vegetable feeders. A few are recorded here as biting man.

Rare in habitations, lives on human blood. Found by Blanchard in a bed at an hotel at Liverpool. The bite is undoubtedly worse than that of Cimex; cosmopolitan. In colour it is ferruginous, shining, legs testaceous; hemielytra slightly shorter and narrower than the abdomen; membranous portion transparent, the apex broadly fuscous. Length 3·8 to 4·8 mm.

Sometimes attacks man, and the bite is very painful. It is 25 mm. long and 8 mm. broad, and occurs in Colombia. It is found also in Cayenne and Venezuela. This like other species is known in South America as bichuque or benchuca.

[A few other unimportant species are also recorded as biting man, such as Harpactor cruentas, in the South of France; Eulyes amœna, from Borneo and Java; Arilus carinatus, Forster, from Brazil. The latter appears to be the same as the Acanthia serratus, Fabricius.—F. V. T.]

[The only Orthoptera recorded as doing actual harm to man are certain wingless locusts found in Africa. The cysticercus stage of a small tapeworm found in rats and man has been found in an earwig (Alcock).

[The strange Hemimeridæ found in West Africa, resembling wingless cockroaches, are parasitic on rats (Cricetomys). Phasmidæ, or stick insects, are said to be able to eject a fluid which may cause blindness if it comes in contact with the eyes.

[A wingless locust—Enyaliopsis durandi, Luc—is recorded by Wiggins374 as injurious to man in Uganda. “The bite of this insect,” it is said, “gives rise to a very nasty eruption, which may extend over the whole body, with high temperature and general malaise. The skin at the site of the bite sloughs away, and generally leaves a large deep cavity, which heals very slowly.”

[An allied species—E. petersi, Schaum—emits a clear yellow fluid, but according to Marshall this does no harm.375 Stannus writes that “for some years I have been cognizant of the fact that among the natives of Nyasaland an allied if not the same species is held to cause skin lesions by the emission of a fluid on the bare skin surface of the body. I have seen cases of ulcers on various parts of the body, for which the ‘nantundua’ was assigned as the cause.” He then describes the destruction of the superficial layers of the skin which he observed after the yellow fluid had been on the skin twelve hours.—F. V. T.]

The larvæ of beetles, similarly to those of some other Arthropoda (myriapods and the larvæ of gnats), have sometimes been observed in man as purely accidental guests. In one case or another, such accounts may have originated through a mistake of the observer. Thus English doctors report the presence of the larvæ of Blaps mortisaga in the stools of human beings, Sandberg of the larva of Agrypnus murinus in his ten year old son, and Blanchard mentions the larva of a beetle that was vomited by a child. All these cases, however, do not represent actual parasitism, although there are beetles living parasitically.376

[Taschenberg records this beetle as having invaded some sleeping apartments adjoining a brewery where stores were kept, and annoying the sleepers at night by nipping them when in their beds.

[This beetle is common in many parts of the world amongst groceries, corn, meal, seeds, dried fruits, etc. It is about 1/10 in. long, much flattened and chocolate-brown in colour. The thorax has two shallow grooves and bears six minute teeth on each side. The jaws are strong, but the bite cannot be very serious.—F. V. T.]

Wingless, the thoracic rings distinct and free; antennæ of three segments; legs very powerful; abdomen with nine segments. [Ten segments are present, but only nine are visible.—F. V. T.] The mandibles transformed into serrated puncturing organs, which are situated in the split sheath of the rostrum; the maxillæ are laminated and have palpi, and more or less conceal the other parts.

The importance of fleas lies mainly in the fact that they act as plague carriers. About 150 species have already been described. The only ones of importance for this work are those found on man and those on rats and mice. The two families in which these are found are known as Pulicidæ and Sarcopsyllidæ.

The eggs of fleas are laid on the ground, on rugs, etc., and in birds’ and rodents’ nests. They hatch rapidly in warm weather and in warm climates, varying from two to five days; in cold countries they may take two or three weeks to incubate.

The larva is a footless creature, pearly white in colour, the head sometimes being darkened, composed of fourteen segments including the head, and although apodal can move with considerable agility. It lives amongst dust and dirt, and feeds upon any organic matter it can find. In about two weeks it is said to become mature, and then spins a cocoon in which pupation takes place.

The cocoons of the common human flea and the fowl flea become covered with dust and dirt. The period of pupal life seems varied, for I have had the fowl flea hatch out in ten days, and others in three weeks at the same time of year.

The adults are blood suckers and cause considerable irritation as well as acting as disease carriers, and in the Sarcopsyllidæ the females attach themselves permanently to their hosts, embedding themselves under the skin, where they become pregnant. Some kinds harbour the cystic stage of tapeworms, and the rat trypanosome passes certain stages in the rat flea. Most fleas have definite hosts, but some, like the rat and fowl fleas, attack man.

The fleas which can carry the bacillus of plague are Xenopsylla cheopis, Pulex irritans, Ceratophyllus fasciatus and Hoplopsyllus anomalus.

The two families, Pulicidæ and Sarcopsyllidæ, can be distinguished as follows:

Thoracic segments much foreshortened, coxæ and femora of hind legs very slightly enlarged	Sarcopsyllidæ.
Thoracic segments normal, coxæ and femora of all the legs much enlarged	Pulicidæ.

The members of this family are not confined to one host.
Three genera are known and tabulate as follows:—
α. Hind coxa without a patch of spines on the inside.
α¹. Hind femur simple	1. Dermatophilus.
α². Hind femur with a large tooth-like projection near the base	2. Hectopsylla.
β. Hind coxa with a patch of short spines on the inside	3. Echidnophaga.

The eyes of the female vestigial. Taken on and behind the ears of Mus rattus in Brazil.

About 1 to 1·2 mm. in length; brown in colour. Eyes distinct. The males only occasionally visit man to bite; the fertilized female, on the other hand, bores into the skin with her head, particularly about the toes of the host, and then attains considerable dimensions. The eggs develop on the soil with a metamorphosis similar to that of the common flea.

[Three other species are found on rats, viz.: E. myrmecobii, Rothsch., from Australia; E. murina, Tirah, from Southern Europe; and E. liopus, Rothsch., India and Western Australia.—F. V. T.]

Section I.—Club of antennæ distinctly segmented only on the hind side.
Key to Genera.
a. No comb on head and thorax.
a¹. The internal incrassation, which extends from the insertion of the mid coxa into the thorax, joins the anterior edge of the mesosternite	Pulex.
b¹. This incrassation joins the upper edge of the mesosternite	Xenopsylla.
b. With a comb on the pronotum only	Hoplopsyllus.
c. With a comb on the pronotum and at the lower edge of the head	Ctenocephalus.
Section II.—Club of antennæ distinctly segmented all round.
Key to Genera.
a. Eye developed.
a¹. No comb on head.
a². Pygidium not projecting backwards; frons with tubercle	Ceratophyllus.
b². Pygidium strongly convex, projecting backwards; frons without tubercle	Pygiopsylla.
b¹. Two spines at angle of genæ	Chiastopsylla.
b. Eye vestigial or absent.
a¹. Abdomen without comb.
a². Hind edge of tibiæ with about eight short and several long bristles, which do not form a comb.
a³. Fifth segment in fore and mid tarsi with five, and in hind tarsus with four bristles	Neopsylla.
b³. Fifth segment in fore and mid tarsi with four, and in hind tarsus with three lateral bristles, there being an additional pair of bristles in all the tarsi on the ventral surface in between the first pair	Ctenophthalmus.
b². Hind edge of tibiæ with about twelve short and three long bristles, the short ones forming a kind of comb	Ctenopsylla.
b¹. Abdomen with at least one comb	Hystricopsylla.

Male 2 to 2·5 mm. in length, females about 4 mm.; reddish or dark brown; head without bristles; thoracic and abdominal rings of bristles on the dorsal aspect, and small hairs directed backwards at the posterior margin. The barrel-shaped white eggs are deposited in cracks in the boards, sweepings, spittoons, etc.; they produce legless larvæ consisting of fourteen segments, which, after about eleven days, are transformed into pupæ; after another eleven days the flea emerges.

In the male the bristles of the flap-like process of the clasper all slender; in the female the narrow portion of the receptaculum seminis long. Originally discovered in Egypt.

This is apparently the chief plague flea. The Indian Plague Committee have proved that this flea is easily infected when fed on plague rats, and that the bacillus multiplies rapidly in the flea’s stomach and that the fleas may remain infective for fifteen days. How the flea infects man does not apparently seem to have been proved, as it does not do so through its bite, but the excrement is highly infective. It is probable that this poisoned fæcal matter gets to the wound caused by the piercing mouth.

Includes the cat and dog fleas. The dog flea, C. canis, Dugès, is found on the dog all over the world, but especially in temperate climates. It also occurs on rats. Man is often badly bitten by this insect and it overruns houses. The eggs are laid on rugs, carpets and dust and dirt and amongst dogs’ hair, but are not fastened to it and fall anywhere. The ova may hatch in about fifty hours and the larvæ live for seven days and then spin their cocoons amongst dust and dirt. The pupal stage lasts about eight days.

The cat flea (C. felis) is widely distributed over the world, and occurs on many mammals beyond the cat, and is also found on rats.

A genus found in North America related to Pulex, but at once recognized by the prothorax bearing a comb.

which is found on the ground squirrel (Citellus beecheyi) in California, and according to Rothschild once found on the rat, has been proved to carry the plague bacillus and to play an important part in plague infection in California.378

This flea is also found on the rat in Europe and will attack man. It is a plague carrier. It has eighteen to twenty teeth on the prothoracic comb and no black spines on the head. The genus Ceratophyllus of Centis has a pronotal comb and three ante-pygidial chætæ on each side. Two other specimens recorded: C. londiniensis, Rothsch., and C. anisus, Rothsch. The former on rats and mice in London, the latter on Felis sp. from Japan and Mus norvegicus in California.

This genus contains a very abundant rat and mouse species, C. musculi, Dugès, which is widely distributed over the globe.

Large hairy fleas, with no eyes and one or more combs on the abdomen. In the Mediterranean area one species, H. tripectinata, Tirah, is common on rats and mice, and also in the Azores. Several others occur on rats and mice. For information concerning these the reader is referred to Rothschild’s papers.