440 
Bs Cie are 
Tur BLOWFLIES OF NortH AMERICA 
PLATE 34 
Callitroga americana (Cushing and Patton) 
Larva, cephaloskeleton, first instar. 
Larva, second instar 
Cephaloskeleton. 
Posterior spiracle. 
Larva, third instar 
Posterior spiracle; b, ‘‘button,’’ p, peritreme. 
Mature larva, left lateral view; asp, anterior spiracle, sp, spines, psp, 
posterior spiracle, at, anal tubercle. 
Typical position of americana larvae in wound (navel of calf). 
Anal area; ap, anal protuberance, 7, inner tubercle, m, median tubercle, 
o, outer tubercle, pc, posterior cavity. us 
Cephaloskeleton; dc, dorsal cornua, dsc, dental sclerite, dphs, dorso- 
pharyngeal sclerite, hsc, hypostomal sclerite, lsc, labial sclerite, 
pssc, parastomal sclerite, vc, ventral cornua. 
