114 INSECTS AFFECTING DOMESTIC ANIMALS. 
species affecting man, and refers to two species, Dermatobia noxialis and 
D. cyaniventris, the species common throughout tropical America. In 
the former the second and third segments are provided with fine spines, 
while in the latter these segments are smooth; and in the former, also, 
the posterior border of segments 4 10 7 are without a range of hooks 
dorsally, while cyaniventris has these segments and also the eighth, 
sometimes, with a row of crooked hooks pointing forward on the pos- 
terior border dorsally. 
Railliet speaks of these bots as at times a veritable scourge to cattle, 
aside from their attacks on man and dogs. 
Family MUSCID2. 
(House Flies and Allies.) 
These are robust-bodied, usually hairy flies, the larvee of which are 
fleshy. footless maggots, living in decaying matter, ordure, etc. 
THE HorRN FLY. 
a 
(Hematobia serrata Rob.-Desy.) 
In the introduction and rapid spread of this insect we have an excel- 
lent illustration of the importance of giving attention to the injurious 
insects of other countries and of taking all possible means to prevent 
their importation. ; 
Fig. 57.— Hematobia serrata: a, egg; b, larva; c, puparium; d, adult in biting position—all enlarged 
(from Riley and Howard). 
The species in hand has been a common insect in Europe, and with 
other members of the same genus recognized as a troublesome insect, 
though apparently no careful study of its life history has been made 
there. 
a a ae 
