SUBFAMILY CHRYSOMYINAE 145 
Third instar (pl. 35, D): Far less robust and slightly smaller 
than americana. Spines (sp) comparatively small, with one to 
three points but more often with two. Anterior margins of each 
of segments 2 to 9 completely encircled with bands of spines ar- 
ranged in more regular rows than in americana; segment 10 with 
band interrupted on dorsum, and segments 11 and 12 with spin- 
ous area restricted to ventral and ventrolateral regions; spines 
wanting on posterior margin of all segments, except for one or 
two rows of small spines on center of segments 7 to 12. Anterior 
spiracles (asp) short’ with rather short branches, the number 
of branches varying from 8 to 12, usually 9 to 11 (average of 
Fie. IX. Callitroga macellaria larvae on sheep. Note the ‘‘honey-comb’’ 
type of lesions in bare area which are caused by feeding larvae, and the 
migrating larvae in the wool. The original wound is located on the upper 
edge of this bare area. Valdosta, Ga., September 12, 1935. 
120 spiracles, 9.81 branches per spiracle). Posterior spiracles 
(pl. 35, E, psp, and F) smaller and more rounded than in 
americana, greatest diameter of spiracles 0.342-0.370 mm. (av- 
erage of 10, 0.856 mm.) ; tracheal trunks leading from posterior 
spiracles not pigmented. Posterior cavity (pl. 35, E, pc) out- 
lined with conspicuous conical tubercles, the inner (2) and outer 
pairs on upper margin equal in size, the median (m) pair small- 
er; on lower margin, the outer pair slightly larger and the inner 
pair smaller than the median tubercles; an additional pair of 
small tubercles situated medially near lower margin of posterior 
cavity; anal protuberance (ap) large, with two pigmented, coni- 
eal, anal tubercles (at) ; spines on anal protuberance in a more or 
