I am getting on with the Forest fly and lately I have been studying the claws. I have only just discovered that along the lower part of the large-curved claw is a saw-toothed edge, and to this the slanting grooves which I had previously noticed run down one furrow to each notch so as to give an enormous power of holding and tearing. I think the thumb claw is also to some degree furnished both with saw- and file-like markings (fig. [22]).
P.S. I can only see the saw and file mark with a good side light, when the claw is examined in natural state, not in balsam.
Much magnified.
FIG. 22.—FOOT OF FOREST FLY, HIPPOBOSCA EQUINA, SHOWING DOUBLE CLAWS, CENTRAL PROCESS, AND LONG PRICKLY BRISTLE; ALSO PORTION OF SIDE OF CLAW OF HIPPOBOSCA MACULATA, SHOWING PARALLEL GROOVES AND SAW-EDGE.
1, Leg and base of wing; 2, base of wing; 3, abortive wing; 5, female fly, with base of wings—all much magnified; 4, puparium, much magnified, and line showing natural length.
FIG. 23.—DEER FOREST FLY (FEMALE), LIPOPTERA CERVI, VON SIEBOLD AND LOEW.
June 20, 18096.
I was very glad to have your note of first capture of Hippobosca (Forest fly) on May 6th. I wonder whether on your Red-Deer (or Roe Deer, if you have them) you find the Deer Forest fly, the Lipoptena cervi. I am having a deal of communication about it as having been observed as a very noticeable infestation on Deer in one locality in the North of Scotland. I believe it is troublesome to people moving in the parts it frequents, but the odd thing about it is, that whilst the females are considered (or conjectured, for it is not quite certain) to be always wingless, yet the male flies are developed with wings and drop them, something like ants, on settling on a host animal. It would be very interesting if you found any of these; they come very near the so-called “Sheep tick” in their nature, only neither male nor female of the “Sheep Forest flies” is ever winged. It is also very curious that from some unaccountable confusion the generic name has gone wrong; it seems obvious it should be Lipoptera, “without wings,” but—it is supposed by some error in printing—Lipoptena, which has no meaning connected with the fly, has got substituted. I think it would be well presently to try to get this put right.
With wings thrown off; also still retaining wings; and wing—all
much magnified. Line shows natural length.
FIG. 24.—DEER FOREST FLY (MALE), LIPOPTENA CERVI, VON SIEBOLD AND LOEW.