DESCRIPTION OF FOOT OF FOREST FLY. 99 
hairs, amongst which the presence of this fly causes such well-known 
discomfort, or even terror. 
This file-sided and saw-edged structure of the large curved claw is 
to be found in our H. equina (see Plates). I have also found it in the 
H, maculata, Leach, the Indian Forest Fly (see figure accompanying 
of portion of claw much magnified), and presumably is to be found in 
the case of other species; but in observation I could only get a satis- 
factory view of the parallel grooves by examining the claw in natural 
Foot of Hippobosca equina, showing double claws, central process, and long 
prickly bristle; also portion of side of claw of H. maculata (also magnified), showing 
parallel grooves and saw-edge. 
condition, dry, and as an opaque object, and also with a bright side 
light. In this way the clear lines of alternating light and shadow 
showed the ridges and furrows excellently, but in Canada balsam I 
was not able to distinguish them. 
The long bristle-like appendage, originating beneath the foot, and 
extending fully to the length of the curved claws (see figure and 
Plates), the ‘‘ poil barbu,” or bearded hair—first, I believe, noticed by 
De Geer in his ‘Mémoires’ on Hippobosea—was very noticeable. In 
these observations, besides other structural details, he notes the 
existence of this foot appendage of a bearded hair, ‘“ poil « barbes,” 
referring the reader for details to p. 288 of the same paper (referred to 
below), where, under the heading of ‘‘ Hippobosque verd’’—the Hippo- 
busca (now Ornithomyia) avicularia, Linn., the Spider or Forest Fly 
infesting birds—he describes the appendage thus :—‘‘ Between the 
‘ pelottes’”’ [pads or pulvilli, Ep.] ‘‘ there is placed a very remarkable 
bearded hair, haying bristles at each side like a little feather, which is 
* See ‘Mémoires pour servir 4 l’histoire des Insectes,’ par M. le Baron Charles 
De Geer, vol. vi. p. 279. Stockholm, mpccuxxvt. 
H 2 
