Torrington House, St. Alban’s,
February 13, 1897.
Dear Mr. Janson,—I hope that in a very few days you will receive your copy of my twentieth Report, in which you helped me so especially about the Forest flies.
I am hoping you may be good enough to help me about the enclosed, or kindly put me in the right path, for I greatly hope that this may prove to be the long-needed observation about amount of wings of the ♀(female) Deer Forest fly, the Lipoptera cervi (fig. [23]). I received a day or two ago a good number, many still alive, or fresh on a little piece of Roe-deer’s hide, which was infested with them even to being in clusters (from Strathconan forest, Ross-shire). On examining, I found on each side, at the hinder edge of the thorax, a little membranous kind of structure with a scalloped edge, and on very carefully raising it I found it was fixed to the thorax by a joint, and was, I think, quite certainly an abortive wing. I saw veins traversing the structure longitudinally, and though the scalloped and notched extremity was irregular in shape, it did not at all have the appearance (to my thinking at least) of being torn. Enclosed I send you half a dozen specimens, one of which has the structure very plain; the others I picked out at random, and what I am very much wishing you would help me about is whether these are females. They have the distinguishing dark brown colour (not the faint yellow colour of the male), and I should say they had the shape of the female, but I am not anatomist enough to be certain. If you cannot with complete convenience tell me yourself could you oblige by getting me a trustworthy opinion. I would most gladly give a most liberal consideration to any one you would get to investigate, for if these are females, we have here the long-wanted observation, and proof that they have abortive wings. I have plenty more specimens if you would care for some more; also I have two puparia.
February 23, 1897.
I am greatly obliged to you for helping me in this matter of the L. cervi. You will remember that you kindly helped me to a sight of a good number of German publications, from which I made large extracts, and, turning to these, I find notes of the male and of the female L. cervi, being found together in the hair of the deer all the winter through, and pairing there and the female depositing puparia. But the matter is much involved by the following statement regarding two varieties in the form of the males by Professor Stein, or Hartmann quoted by Stein: “The first are pale yellow, and the abdomen is slender and shrivels considerably after death; the latter are more yellow brown, their abdomen is wider and firmer, and the external organs of propagation clearly observable.” There is a deal about abortive or shed wings, but the writers are under uncertainty. My belief is that our only hope towards clearing up the matter is our own observation, and if these creatures are really females, we have got the information that was being sought after. But do not let me tax your very great good nature too much. If you could give a specimen or two to Mr. Verrall and to Mr. Austen I should like it, and you would hear what they say, and I would replace them to you. I have two puparia which I suppose are not likely to develop till towards the end of summer.
April 16, 1897.
I have been so fortunate as to find a puparium of a Deer Forest fly lately sent me in a consignment from Strathconan, and this gave me an opportunity of communicating with Professor Jos. Mik, Vienna, and he pronounces the specimens I sent accompanying to be females. He writes me (and I think it very kind of him to take the trouble) an exceedingly long letter, full of information and references, extending in a very small handwriting over five and a half large pages of note-paper, and, as he justly remarks, I have some difficulty in reading it!
I think of getting Mr. Pillischer to make some preparations of the L. cervi ♀and their abortive wings so that we may have material for a good figure. Professor Mik is fearfully particular.
May 12, 1897.