LOUSE-FLIES. 139 
f I; LOUSE-FLIES. 
(Hippoboscide, Pupipara). 
Louse-flies are very peculiar insects, belonging to the 
order of flies (Diptera); both their form and mode of repro- 
duction are very abnormal. They are parasitic, living upon 
the bodies of mammals and birds. Closely allied insects, 
with similar life-histories, are found upon bats and the honey- 
bee. Some louse-flies are winged, others are not, but in the 
latter case we find on each side of the thorax, near the an- 

Fig. 120.—Sheep-tick and enlarged foot. Greatly enlarged. Original. 
terior angle, a small round spot, indicating where the upper- 
wing should be, and near the posterior angle a small pro- 
jection which seems to represent the balancers, or remnants 
of hind wings. All louse-flies possess a depressed body and 
widely separated, short, and stout legs, furnished with 
strong claws, which in some cases have teeth. The last joint 
of each foot bears a feather-like organ, probably used to coil 
around the hair for a stronger foothold, (see enlarged foot 
in fig. 120). The head, nearly as wide or wider than the 
thorax, is sunk in the same without a distinct neck; the 
feelers are very short, apparently one-jointed, with a term1- 
