STRUCTURE OF FEET. 



53 



Legs rather long (when extended flatly, they appear very long), of 

 great strength, and tawny yellow in colour, variously ringed, or 

 clouded, or otherwise varied, with brown or black. 



Each foot (or tarsiis) is terminated by a pair of claws, each of the 

 pair being formed of one large, very strong, much curved, black claw, 

 at the outside of which is placed another much shorter and thicker, 

 forming a kind of thumb-like appendage to the main claw. See figure 

 below. On placing the curved claw in a good light, it can be seen 



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. 



(with the help of magnifying powers) that the lower parts of the sides 

 are furrowed by minute grooves placed parallel to each other, and 

 that the lowest part of the claw has, running beneath it, a regularly 

 serrated, or scalloped, edge, each groove running down to a notch in 

 the saw-like edge. This structure I have also observed in the Indian 

 Forest Fly, Hippubosca mnculatn ; see figure accompanying of ]witio7i 

 of a curved claw very much magnified. Consequently on this peculiar 

 structure, when the fly presses the sides of the curved claws together, 

 they form a kind of flat-sided forceps, perfectly adapted for holding 

 fine objects like hairs, amongst which the presence of the infestation 

 causes exceeding discomfort, or with horses unaccustomed to it quite 

 uncontrollable terror. 



Beneath the foot and between the cushions, or pulvilli (see figures 

 above, greatly magnified), is a long stout hair, or rather bristle, ex- 

 tending fully to the length of the curved claws, and bearded with side 

 hairs. The appearance of this appendage varied much according to 

 the circumstances under which it was observed ; when seen in natural 

 condition, being well described as a "somewhat plume-like body," but 

 when examined in Canada balsam, instead of the whole length of the 



