Eel-worms—Lady-birds—Wheat midges—Resignation from the Royal Agricultural Society—Wasps—Study of Norwegian and Swedish—Gall mites—Boot beetles—Experience of publishing.

Representative letters to five foreign and colonial scientific entomologists have been gathered into this chapter, among other reasons to show the diversity of Miss Ormerod’s work, carried on in close touch and in the most agreeable relations, with the highest wide-world authorities on various specialised branches of her subject.

To Professor J. Ritzema Bos, Amsterdam.

Dear Dr. Ritzema Bos,—I have not written to you for a long time, partly because I had nothing of sufficient importance to allow me to submit it to you, but also because both my sister and myself had rather severe illnesses.

Enclosed I beg to send you some pieces of potato, which I think it is just possible may be infested by (or at least have now) some slight presence of Tylenchus devastatrix (eel-worm, fig. 47). I received several tubers this morning from near Helensburgh, in Dumbartonshire, Scotland. Mr. Robert Howie, the sender, writes me that a large field recently dug up by him was very much damaged by being badly “scabbed” in the same way as the samples sent. But, when I came to examine the so-called “scabbed” parts after washing, the surface for the most part looked to me more as if it had been gnawed by some larvæ, than if it were a diseased state of coat. The skin of the potato is often left overhanging. I was going to suggest to Mr. Howie that he should search for Agrotis larvæ, or Melolontha (Cockchafer), grubs, but examining further at the end of one or two tubers, where the skin was still in its natural state, excepting small patches of what was as yet only a slight discoloured roughness, I found a few eel-worms. They were so few that they evaded me when using the higher power, but in one instance I thought I detected a bulb near the head end. I am afraid I may be taking up your time with what is of no importance; still I thought I should like to send you some pieces, and if the attack is one of any interest I would gladly forward more. The eel-worms I have seen are all anguilliform, the largest was about as long or longer than the largest T. devastatrix I have seen, the others were smaller. Mr. Rochford has been carrying on with great care and precision his experiments as to poisoning Heterodera radicicola (root-knott eel-worms, fig. 49). He has tried about forty different applications—noting the amount given and the effect on the eel-worms and the plants. I certainly hope that a few will show successful results, but he is very careful, and is now going over his series of experiments a second time, that he may be quite certain before coming forward with statements of effects. As soon as I know anything of interest I shall be very glad to be allowed to tell you; Mr. Rochford has given me permission. I do not know as yet whether he will bring forward his results himself, or leave it to me to do. Pray believe me, with best thanks for all the kind assistance you give me.

As I think that you have either returned home, or will soon be returning, I now (with your kind permission) send a few more of the “scabbed” potatoes, which it seemed possible might be infested by Tylenchus devastatrix. If it should be convenient to you at your best leisure to make any examination, and to let me know results, I am sure I need not say how acceptable your information would be, not only to myself, but to many interested in the cause of this external deformity. I send the potatoes in a little tin box by parcel post. Recently I have had rather an interesting observation of the little black, somewhat pubescent, “lady-bird” beetle, Scymnus minimus, as a feeder on Red spider, Tetranychus telarius. I have not been able to find any account of its life history, so I have had great pleasure in watching its progress from larval to imago state. It seems to me to be greedily carnivorous; after a few hours’ want of food during their journey to me, the larvæ set to work to feed on what they could pick up on the back of a leaf infested by red spider, as eagerly as sheep on fresh grass; and as I found one day only a single larva remaining of three or four confined together, I suspect it was this survivor who had reduced his brethren to the small remains which were all I found. The final changes were rapid, for the above happened on August 28th, and shortly after it had pupated, and yesterday I found the little black lady-bird in most active condition.

I have heard nothing further at present from Mr. Rochford about his Heterodera experiments. I think I must remind him soon that he kindly promised me a report.

I have been quite sorry for a long time that I have had no specimens which would be of interest to you. I was afraid you might think I was not attending to these subjects, but now I have received a cucumber root quite beset with galls, of which I forward you a portion. It is from a nursery gardener at Rhyl, in Flintshire, North Wales, where they are much troubled by cucumber and tomato plants dying, some of both kinds having the “roots covered with galls but some have not.” Messrs. Maxwell and Dalgliesh sent me some of the roots without galls, from plants that were nearly dead, but I could not discover the cause of the failure of these. On such inefficient examination as I make, I find in the soft pulpy centre of the larger galls some anguilliform nematodes, which I conjecture to be males, or larvæ, of the H. radicicola, but so far as I searched I did not find females; there were a fair number of eggs. On cutting the pieces of plant into fragments for packing I find the stem just about the ground-level much beset with diseased growth. I have not, however, delayed to try to examine this, for I might be only wasting specimens. Messrs. M. and D. have five houses fifty yards long each, so the infestation is a serious trouble to them. They tell me that they clear out all the soil each year, and bring fresh soil in. It “is rich alluvial soil.” They have tried lime, soot, and nitrate of soda without effect, and I should certainly say that something requires alteration for the extermination even of an infestation much more easily dealt with; for they are troubled by millepedes (fig. 27), and also there are such great numbers of Geophilus (centipedes), that there must, I think, be something amiss whether these live chiefly on vegetable matter or on small animal vermin.

Some inquiry about H. radicicola has been sent to me from Glen St. Mary, Florida, U.S.A., but no new information.

On Saturday, Professor Ainsworth-Davis wrote to ask me to write a preface to his translation of your “Zoologie,” and it will gratify me very much indeed to prepare such a one as I hope may please you. Your book will be a very valuable addition to our educational series, and I shall like very much to be permitted thus to appear in colleagueship.

This matter of the ? Tylenchus devastatrix in the cortex seems to me most perplexingly curious. I cannot venture to form an opinion; I have not the knowledge requisite, but looking at these Tylenchi being smaller than T. devastatrix is customarily known to be, and also their occurring in a locality where devastatrix is not known, the idea just floats in my mind whether they may be ♂ (males) or, alternatively, larval Heterodera schachtii (“Beet-root” eel-worm).

But perhaps I am almost wrong in taking up your time with a mere idea, as you work on definite proof, and though the shape of those I mentioned to you much resembled your larval H. schachtii, I had not sufficiently high powers to be sure of the species. I have been trying to make out whether there is ever a definitely formed opening for the exit of the contents of the ♀(female) schachtii. In examining one specimen I found a circular orifice with what appeared to me a regularly formed edge—not a merely torn one. On putting this in glycerine under a thin cover-glass, and very lightly pressing it, there first came out a number of little eel-worms, without disturbing the condition of the orifice. I was, however, so desirous that my sister should see the interesting sight that I called her, and when I looked again perhaps in a couple of minutes, the regularity was gone; the outer skin—the skin rather of the female—was cracking irregularly from the aperture and giving exit to a mixed collection of eggs and wormlets. I have tried to find another instance but without success. Very many thanks to you for also sparing time to explain to me the meaning of the word “schaŭmerde.”^[80] Now I quite understand and am very glad to know about it. Thank you also for your kind permission to use some of your figures of schachtii.

I should very much like to have some specimens of the hop-growth called “nettle-headed,” but I have only received a very few leaves, in which I did not see anything amiss.

I received a specimen (though I suppose this is not rare) of the large Coccinella ocellata (Eyed lady-bird). What a pretty creature it is! I had never seen it before.

Also from a North British correspondent I received a number of what I do not think could be other than larvæ of one of the Staphylinidæ, which were doing mischief by feeding in turnips or their flower stems or leafstalks. They looked grey to the unassisted eye; magnified, they were whitish with grey patches along the back, and they much resembled the fig. by Professor Westwood (see p. 167 of vol. i. of his “Classification of Insects”), of which I give a rough tracing of the magnified larva and line showing natural size. Professor Westwood found numbers of these larvæ feeding on turnips, but, unfortunately, he does not give even the generic name. They are obviously very destructive, that is, those sent me.

I have been most carefully studying your observations on schachtii in oats with great pleasure and profit. With kind regards and ever with many thanks, believe me,

To Dr. W. M. Schöyen, State Entomologist, Christiania.

Dear Sir,—I have long been in your debt for grateful acknowledgment of your kind thought in sending me from time to time copies of your valuable pamphlets, and also of your portrait, which I have much pleasure in adding to my collection of portraits of the leading entomologists of the world. But I trust you will forgive my long silence because for a long time (that is, since last autumn) until about three weeks ago, I have been a great sufferer, and it has been with difficulty I have been able to keep up to work.

May I ask your kind acceptance of my fifteenth Report (accompanying by book post), and a little brochure I recently arranged by special request; also with them may I place a copy of my portrait, recently taken,in your hands? I value your pamphlets which you kindly send me, much; but, unfortunately, I have never been able to master your language—so when I have read the title, if it be a subject bearing specially on my own work, I get help from a linguist to enable me to benefit. Trusting that for the reasons given you will pardon my long silence.

I thank you very much for being so good as to tell me of the appearance of the Cecidomyia destructor (Hessian fly, fig. 15) in Norway. This observation of the further spread of this troublesome barley pest is very interesting to me, and I am also greatly obliged to you for letting me have the characteristic specimens of puparia. There is no doubt that these are the chrysalis cases (the “flax-seeds,” as we call them here) of the Hessian fly. I at once wrote to two friends to endeavour to procure the specimens you name, and it would have been a great pleasure to me to send them at once, but I much doubt whether I shall be able to procure any of the Wheat midge, C. tritici; I have not got any myself, nor have my two colleagues so far as they see.

About the Hessian fly, I have been more successful. I have secured some specimens well put up for the microscope. It is too late this evening to repack them properly, but I hope to send you three slides to-morrow in a registered letter, of which, with very great pleasure, I beg your kind acceptance. Should they not reach you in proper condition, you will oblige me by letting me know, that I may try to replace them. I should hope that the thoroughly well-advised treatment which you are endeavouring to get carried out in the infested district will be successful. I have great confidence in the efficacy of destroying the puparia in the screenings or siftings; and ploughing so as to turn down the “flax-seeds” also quite certainly answers well.

One special insect trouble during the past season in this country has been an unusual prevalence of wasps, Vespidæ, of various species. They caused much injury and loss by destroying fruit, and also were very troublesome by attacking horses ploughing, if their nests were turned up. I hear that they were also troublesome in Holland, and in the Hartz districts of Germany. Should you write to me, I should be very much interested to know whether they were also unusually plentiful in Norway.

I beg to offer you my best thanks for your very acceptable letter of the 31st of October. Indeed, I am greatly obliged to you for not only kindly giving me your own information as to amount of wasp presence observed in the past season, but also the translation into English of the account of their great appearance at Tromsö in 1883-4. This is exceedingly interesting, and also very entertaining. I have enjoyed reading this spirited account uncommonly, and I shall like very much to add it (of course duly acknowledged) to my paper on wasps in my next Annual Report.

[The translation appeared as follows:—

“In the years 1883-1884, there was an unusual prevalence of them in the Arctic Norway, especially at Tromsö and other islands in the vicinity. Mr. J. S. Schneider, Conservator at Tromsö Museum, writes in the Swedish ‘Entomologisk Tidskrift,’ 1885, pp. 148, 149, about this matter as follows:—‘Who can tell all the tears which these wicked animals have squeezed from the poor children, or the swearings which the mowers have thrown out, the half-shut eyes, and the swollen hands and cheeks which have shown forth in the autumn months of these two years? Perhaps this may appear an exaggeration, but it comes, however, pretty near the truth. They built their nests everywhere, in the earth, in stone walls, behind the wainscottings of the houses, under garden benches, on the trees; it swarmed with wasps on all the flowers and bushes, the windows were filled with them, they crawled on the plates of the dining-tables, licked of the dishes with preserves, crawled under the clothings, and in the hair, and did not at all spare the ladies! When one was going in the woods, a humming warbling was heard, which is still sounding in my ears; wasps everywhere, it was almost a despair,’ &c.

“I have not seen anywhere in the southern districts of our country the wasps so exceedingly numerous as they must have been in Tromsö in the said years. The species occurring here are: Vespa crabro, media, saxonica, and var. norvegica, holsatica, vulgaris, germanica, rufa, and Pseudovespa austriaca.” (W. M. S.).]

Now I have much pleasure in begging your acceptance of a few pamphlets sent accompanying by book post—three on Hessian fly and one on Paris-green. Two of the Hessian fly pamphlets were condensed notes regarding its first appearance here, the other a report in full of the communications of my correspondents. I wished very much to send you a similar detailed report of the first year’s observations of this Cecidomyia destructor (fig. 15) in Britain, but as yet I have not been able to find one remaining. Every year since the first appearance of this infestation amongst us, I have received some amount of information as to its greater or less presence, and I have given, so far as I could, my best attention to it. If it should happen that there is any point on which you would wish a reply to any inquiries, I would with pleasure do my best to answer fully, and would think myself honoured, as well as be very much pleased to be in communication with you on the above subject, or any other point of injurious insect presence.

[On the subject of wasps, Miss Ormerod wrote to Mr. Edward Connold on January 15, 1894:—

“I am very glad that you were able to procure my late brother’s book on “Social Wasps” and that its perusal gave you pleasure. You ask me how the combs were removed from the nests. I do not know how my brother managed it, but I found the matter very easy, as long as the nests had been so recently taken from out-of-door localities, that the paper had not become too dry to be operated on. Indeed, the damp condition induced by the first stages of the very nasty state that combs with dead grubs get into, rather facilitated work than otherwise. The first thing in working on a nest of any size was to get a pair of scissors, long in the blades, thin, and also very sharp. Then carefully make a clean vertical cut through the paper-case of the nest from the entrance below nearly to the top. Through this great gash I had no difficulty in removing the combs—so to say (although it is a disagreeable word) “eviscerating” the nest. I began with the smallest and lowest comb. Inserting my scissors horizontally I snipped through the little paper pillars by which it was connected with the comb above and withdrew it in a very convenient way, with fingers or forceps (or very likely by help of the scissors) through the opening. Continuing this process I do not remember that I ever failed to clear out the comb successfully. It did not always require to be entirely removed, if I recollect rightly. I think sometimes the upper comb did not require removal. When all was cleared out, I filled the empty paper case with cotton wool, and applying plenty of gum to this below the slit, I very gently pressed the paper back to its former position, and if the work had been dexterously done, the injury did not show much. If the paper had been broken of course the damage showed, and it was requisite to be careful that the gum or adhesive mixture used for keeping the cut edges in their places did not run about. Sometimes where circumstances permitted, I cut a little aside from the straight line in places so as to secure an uninjured piece of a layer to hide part of the slit. In this way very pretty specimens could be arranged, showing both nest and comb. I have been preparing a long paper on the wasp attack of last year for my next Annual Report. I have had very good contributions, and hope it may be liked.

“It will give me great pleasure to attend to any inquiry the Hon. Sec. of the Museum may care to send me as to starting a collection of pests to agriculture, and I think I might be able to help with suggestions where specimens are procurable.

“Many thanks for your suggestion as to membership, but I do not care to belong to more Societies than I can possibly help, so I hope you will forgive my not accepting your kind offer.”]

Dear Dr. Schöyen,—In reply to your inquiry whether any measures are being taken in this country to prevent the introduction of the San José Scale, Aspidiotus perniciosus, I am not aware of any such measures being in contemplation. I have not heard of anything of the kind being proposed, nor have I seen any mention in our newspapers of preventive measures being contemplated in regard to imports. My own impression is that we are not likely to suffer from it. With our island climate (as a general thing, and as especially observed by Dr. C. V. Riley) the injurious insects of the Continent of America rarely establish themselves here, although ours adapt themselves to the American Continental circumstances, and this Scale appears to be remarkably susceptible to damp and cold. The Bulletin by Dr. John B. Smith, Entomologist of the New Jersey Experimental Station, published November 27, 1897, says, p. 6, “The Scale does best with us in dry, warm weather. It does not like dampness, nor shade, and will die out in a cold, moist locality. Large trees with dense foliage are therefore least troubled, and a dense mass of vegetation shading the ground completely will be infested only towards the tips of the twigs or branches nearer the surface, where sunlight and air are most abundant.” I greatly hope, therefore, that even if this injurious attack should come, that it will not establish itself to a serious extent, as shade is a characteristic of many of our orchards.

Our chief trouble at present is an attack of eel-worms, Tylenchus devastatrix, on red clover, Trifolium pratense, causing what we call “Clover-stem sickness.” I never knew the attack so widely prevalent before. But I hope that with the measures which I draw attention to in my recent Annual Report we may do some good.

Relatively to the San José Scale, I find, from some information received this morning, that Mr. R. Newstead, Curator of the Grosvenor Museum, Chester, has lately attended by request at the Board of Agriculture, and stated that this infestation had not established itself in any way in this country. Also that he had not heard of, nor had he seen any instances of its presence, although he had made diligent search for it at Liverpool, &c. He thinks the matter is a “scare,” and that the insect is not likely to establish itself here. In this opinion (the document before me states) he is supported by our Entomological Society. Mr. Newstead is, I believe, excellently qualified to form an opinion on the subject, as he is a practical Economic Entomologist, and he has also made the Coccidæ a subject of minute investigation. This I should say was more important than the views of a meeting of our Entomological Society, of whom few, if any (excepting Mr. Douglas), have, so far as I am aware, studied Coccidæ to an extent approaching Mr. Newstead’s observations, and have no special bias towards applied Entomology.

The above will perhaps be of some interest to you as the nearest approach I am able to make to a reply to your inquiry, and I beg you to believe me.

To Dr. Enzio Reuter, Helsingfors, Finland.

Sir,—In acknowledging receipt of your obliging letter of the 8th of October, received here on the 12th, permit me to say that I think it not only a pleasure, but an honour, to be in communication with the leading Entomologists who, like yourself, are working for the good of their countries. I thank you much for your letter.

First, about the Cecidomyia (Wheat midge) larvæ (fig. 62) on the Alopecurus pratensis^[81] (Foxtail grass), I cannot remember that any further observations were sent me about it, nor have I noticed anything in publications which come to my hands. My correspondents often send me specimens and details of some infestation which has caught their attention, but it is with the greatest difficulty in many instances that I can induce them to continue their observations for successive seasons, and the development of the imagines of the Cecidomyiæ from the early condition is much more trouble than they care to take.

By book post accompanying this letter I forward to your kind acceptance a copy of my seventeenth Report. In the pages of the Report I have placed copies of various leaflets. These, you will see at a glance, are not at all scientific, but intended quite for popular use by our farmers, therefore I have used the very simplest words I could.

You are good enough to offer to send me copies of some of your future reports in connection with Economic Entomology. If you can spare them I should value them very much. For although I am not able to understand more than a word here and there, yet with the help of the dictionary I can make out enough to see whether your information is applicable to the conditions here, and I can get a good translation made for me. I can read German and French, but I am sorry not to be able to write with ease in either language.

Dear Sir,—I had much pleasure in receiving your kind letter yesterday, and also beg you to receive my very hearty thanks for your kind and valuable gift of so many of your writings received on the day before. But now I am going to ask you a further favour. At your leisure would you oblige me with the name of a dictionary which would help me to understand them? I do not understand Norwegian, but, with the help of the Dano-Norwegian dictionary of Mons. A. Larsen, I can manage to make out what I especially need from Dr. Schöyen’s writings, which he is so good as to send me. But now I have been trying to translate your few lines on Charæas graminis (Antler moth) (chap. XIII.), and either from my own ignorance, which I much regret, or from not having the right dictionary, I have not been able to read them.

P.S.—It pleases me very much to hear from you that you approve of my reports, and it is kind of you to mention it.

I thank you most heartily for sending me this useful dictionary. It is just what I was needing. With this help I can already make out short pieces of your reports and publications, which is a great pleasure and profit to me. It really was quite a vexation to see what I wanted so much to study and yet could hardly make out any connected meaning. I only just write now to say that both for your kind and helpful gift and your letter accompanying I thank you most heartily.

I did not at once acknowledge your Report on Injurious Insects which you have sent me because I thought very likely you would send me a few lines about mine, and now I beg to acknowledge your note with many thanks. What a vast sum it is that you mention as the loss [about 5,000,000 Finn. Marks = ca. £200,000, in the years 1889-1891] caused by Charæas graminis, Antler moth (fig. 4)! I am so sorry that I am not able to read your reports, which, from the little bits I can pick out here and there, are, I see, so valuable and would help me so much. But please not to think that they are wasted on me, for I learn a great deal that helps me, and when there is something that I particularly wish to know I get the passages translated.

I beg that you will never for one minute think of taking up your valuable time in writing to me at length about my reports. If you can at any time (as you have so nicely done in your letter received to-day) tell me that you think them serviceable, this is a most pleasant encouragement, for which I am grateful, but I know well what a tax it would be to write letters, so to say, merely for compliment. Pray believe me, I should indeed be sorry thus to trouble you. I value your writings that you are good enough to send me very much, and I got a serviceable Swedish grammar and studied it when I could get time, so I can make out a little now; at least so much that I can see where what I wish particularly to understand is, and get it properly translated. Accompanying I have much pleasure in sending two copies of my little brochure on Paris-green. I thought perhaps M., your brother professor, Odo M. Reuter, whose pamphlet on C. graminis I have studied with much benefit, might care to have one.

Many thanks for kindly giving me a copy of your work on the “Zwei neue Cecidomyinen,” which I am very glad to possess. Your minute description will be a most valuable assistance in identification. This year I have only had one report of presence of C. destructor, but there has been a great deal of insect presence, and sometimes of kinds not often observed here.

But the chief point of general interest, I think, has been what to do about the Hippobosca equina (Forest fly, fig. 18), relative to some of our military manœuvres in the New Forest, which is its especial English locality. I do not know whether you have the infestation so far north as your country? It is very troublesome at times here.

I should be very glad to help you if I could by reference to publications on “Silver-top” or “White-eared” wheat, but I am not aware of anything having been written on it in this country excepting my own short and meagre notes in my twelfth Annual Report, for 1888. Specimens are sent me occasionally, but—as by the time that the top of the wheat (or grass) has faded so as to draw attention to the injury, the insect, if insect was there, has gone—I have never been able to identify the cause of the mischief with any approach to certainty. I conjecture the cause to be the presence of some species of thrips. The American observations point to this, but these you probably are well acquainted with (and, indeed, it is not these you are inquiring about). In my notes I mention the peculiar manner in which the injured upper part of the stem can be withdrawn, the stem having been apparently severed about three or four inches above the uppermost knot. In the only instance I have seen in which the attack was still in progress (that is, the stem was not already parted, although it cracked asunder on being pulled), I found that at the point of fracture the straw tube had within an irregular swollen growth, what might be described as a granulated growth, filling up the tube; also the cross-section showed small open cells which had been cracked across in severing the stem. I had specimens of the attack also on barley, and at the time I was inclined, from the absence of all insect appearance, to ascribe it to some vegetable disease, but in the years that have elapsed since then it has appeared to me more likely to be attributable to thrips.

I am afraid that there is not anything worth your study in the page and a few lines of my remarks, but if you would care to see it, I would gladly direct a copy of my twelfth Annual Report to be sent for your acceptance. I would do so now, but I have not an unbound copy by me. Many thanks for your own publications which you have kindly sent me. I have read with great interest your remarks on the Argyresthia conjugella, Zell.^[82] We have an apple attack here occasionally noticeable which agrees well with the characteristics of this infestation, but I have never been fortunate enough to identify the cause.

To Professor Dr. Alfred Nalepa, Gmunden, Vienna.

Monsieur,—I am very greatly indebted to your kindness and courtesy in taking the trouble to give me all the very valuable and helpful information which you favoured me with in your letter of the 28th July. I also thank you much for your permission to make some extracts in my Annual Report from the information which you have placed in my hands. This is a very great favour, and you may rest assured that I will most fully acknowledge my debt to yourself. From the study of the pamphlet which you were good enough to send me I have already benefited largely. But I earnestly pray you, do not let me intrude on your kind liberality for any work that I might be able (if you were good enough to give me the name) to purchase. My London booksellers are accustomed to procuring Continental publications for me, and I am feeling myself so greatly indebted to you for valuable information that I am quite uneasy at not being able to reciprocate as I much wish. I have delayed writing in the hope of being able to procure some specimens, but as yet I have only the enclosed (Pear leaf blister galls, ? of Phytoptus pyri) to send to you from trees in my own garden, and these I am afraid will be of little interest. Your valuable list of infestations has shown me that there are very many kinds of Phytoptus attack that I had no idea of the existence of, and I will indeed try to be of some service to you.

By book post accompanying I beg your kind acceptance of the current number of my Annual Report, in which are some remarks on a species of Entedon (or Entedonidæ, parasites of Dipterous leaf-miners especially) which we found in currant buds in watching for what we hoped might prove a parasite on the Phytoptus. I fear my report will be of little interest to you, but I just beg you to accept to show the kind of publication.

I postponed replying to your kind letter of the 7th in the hope that I might have something of interest to send you, but I have only been able to procure the enclosed Prunus galls. They are from Toddington, Gloucestershire. I rather fear they will wither on the journey, but I forward them because the twigs have something amiss with them, which just possibly may be owing to Phytoptus presence. Thank you much for giving me the name of the Phytoptus pyri, which I have noted at p. 296 in your “Katalog,” which you were good enough to send me, and which is of truly valuable assistance. My booksellers will, I hope, before long procure me five or six of your publications either in separate impressions or in the parts or volumes in which they were published, and then I shall hope to have the information that I am much wishing for, without troubling you personally. But should the special attack, which I desire to understand better, not be specifically described, then I should indeed be very thankful to avail myself of your kind permission to ask for further information, and a sketch would be a most valuable aid. I have too great a respect for the time and work of scientific men to intrude if I can possibly help it, and I am very grateful for the important help which you have already given me.

I am greatly obliged for your kind letter received two days ago, and it is so very good of you to have taken the trouble of writing the names of the various portions of the Phytoptus on your plate accompanying so clearly for me that I hardly know how to express my thanks sufficiently. This is indeed a most acceptable help, for there were some of the quite minutely technical terms that I had failed to make out the meaning of, and now you have most excellently got over my difficulties for me, and I thank you very much for the same. Since I wrote to you at Gmünden I have had great pleasure and benefit in procuring some of your valuable publications, so full of excellent descriptions and figures. One of these is the separate impression of your paper, read on January 24, 1889, with 9 plates, including p. 11, of which you have now sent me this valuably explained copy.

Another—the separate impression for February 13th—contains description, p. 11, and figure, plate iv., of Phytoptus pyri, and I have also a copy of your “Genera und Species der Familie Phytoptidæ,” 1891. Now I think, thanks to study of your clear descriptions, I have a fair knowledge of the characteristics of a Phytoptus, and of the divisions of the Family Phytoptidæ. When I publish my next Annual Report I should very much wish to give my readers some better information than I have hitherto been able to do, and to point to them from what source I obtained it, and how they may obtain it for themselves. I think I have your kind permission to use one of your figures. I am therefore having a very careful copy executed of your P. pyri (plate IV., fig. 1), of the two claws (in your Genera and Species, plate ii., 9a and b), together with an attacked leaf from life (fig. 64).

Your part would be a most soundly valuable aid to readers here, for really and truly I doubt if more than very few among us are aware (say) that the legs of the Phytoptus are made up of claw, tarsus, tibia, and so on, much less that the claw is of this peculiar shape. I confess to you I was ignorant of this myself. I should like to give a part of your description of the P. pyri to show what a description ought to be; also to allude to the species which you were so good as to name for me, and to your principle of classification (p. 317 of “Katalog”). Should any of this not be according to your pleasure, I beg of you kindly to tell me. I should indeed be ungrateful if, after all your kind help, I trespassed on your information against your wish. Should you allow it, you may depend on me to quote accurately, so that my quotations will send readers to your works, not enable them to use my report as a robbery of you; also I would fully and honestly acknowledge the source of my information, and be truly grateful. I wish I could send you specimens. Would you care to have some galls of the Phytoptus ribis from black currant in their (I think) very unusually advanced condition for this time of year? I think I could procure some from Kent.

It is with regret that I read in your letter that you are not in strong health. But if you could work less severely might not you hope to have benefit? The excessively minute work of your elaborate investigations must be exceedingly wearing. In my own observations (which, indeed, are not to be compared with yours) I always find they tell very much on my health if I have at once to overwork my sight with the microscope and my mind in the record of my observations. But I have not robust health, so that I can sympathise. With renewed thanks for the welcome contents of yours lately received.

I am greatly obliged to you for your kind present of your “Beiträge zur Kenntniss der Phyllocoptiden,” with its first-rate descriptions and magnificent figures. It is a very great advantage to me to be in possession of your noble work on these creatures, and I feel myself very much indebted for all the great help you have given me.

About the Phytoptus ribis. I delayed replying because I thought that if any thoroughly complete description of this Phytoptus had been published by Professor Westwood it would be sure to be known of by Mr. W. Hatchett Jackson, of Keble College, Oxford, who was Professor Westwood’s chief assistant. But he tells me that “under the generic name of Acarellus I can find nothing but a brief paragraph without figure in the accounts of the meetings of the Entom. Soc.” Mr. Jackson adds, “I remember the occasion very well, and making slides for him from specimens in our own garden. I shall search for those slides in the Hope Museum.”—W. H. J.

After some search here I found the enclosed, and as I think you would desire to see the fullest account which I believe Professor Westwood published, I have detached the page. If he were still with us I know how he would have delighted in your splendid unravelling of what was then a mystery. At your best convenience, when you have quite certainly no further use for the page, perhaps you would kindly let me have it back.

In my own early observations of the habits of the Currant Phytoptus I noted it as P. ribis, Westwood, on the authority, or rather after the example, of Mr. Andrew Murray (see “Aptera,” p. 355), for we had not in those days any more trustworthy and accepted guidance, but as to comparing these with such a work as yours, no one with the least atom of knowledge would think for a minute of such a thing.