10 
BULLETI] . PUERTO RICO EXPERIMENT STATION 
FiGURi 2. — 1'rotozoan and external paraail rto Etican cattle: A.a, >d evils 
showing tick-fever parasites (from Btilea, 1931). l<< . Red blood ceiis sh< 
plasma (from Btilea, 1931). C, Coccidia from cattle, x ''»•"»" (from Wilson. 1931). 
I>. Cattle tick female, -4 (from UraybiU). F. Hornfly, <5 (from Riley 
and Howard). Q-, Extracting a grab or warble from a cow's back (from Bisbopp. 
Laake, and Wells). //. Tail louse, B. /. Bhort-nosed ox Lous* - /, Leeches 
anengorged with blood. A". Btahle fly, adult female, side view; with blood, 
(from Biabopp). /.. Screw-worm maggot, sid<> view, • 5 (from Bisbopp, Mitchell. 
and Parman). .1/. Psoroptic mange mite, female; dorsal view, ■ 4<» (after Salmon and 
Still 
