SUBFAMILY CHRYSOMYINAE 133 
tral border as to appear bilobed; peritreme (easily distinguish- 
ed in later instars) not apparent; anal protuberance, located - 
ventrally on last segment, with two conical fleshy projections, 
the anal tubercles; a group of spines situated anteriorly and 
posteriorly on anal protuberance; two or three rows of spines 
also present between anal protuberance and lower margin of 
posterior cavity; tubercles bordering posterior cavity poorly de- 
fined. Cephaloskeleton (pl. 34, A) consisting of a pair of large 
pharyngeal sclerites, composed of paired dorsal and ventral 
cornua and a rather short anterodorsal projection; pharyngeal 
selerites apparently not joined anterodorsally as in later instars; 
ventral portion of pharyngeal sclerites extending anteriorly and 
joining the hypostomal sclerites, which in turn articulate with a 
ventral basal portion of the labial selerites; parastomal sclerites 
paired, slender, extending anteriorly from pharyngeal sclerites 
just above hypostomal sclerites; labial selerites paired, small 
elongate, bearing a group of about six small hooklets; above and 
between labial sclerites the unpaired supralabial selerite which is 
present only in first-instar larvae; length of cephaloskeleton from 
tip of labial sclerites to posterior extremity of dorsal cornua 
ranging from 0.24-0.27 mm. (average of 10 specimens 0.26 mm., 
average width at widest point 0.27 mm.). 
Second-instar: More robust than previous instar, length and 
width of newly molted specimens approximately 3.5 and 0.6 
mm., respectively; fully developed second-instar larvae from 
6.3 to 7.4 mm. in length and approximately 1.5 mm. in width. 
Heavily armed with large dark spines, the larger ones measur- 
ing approximately 55 microns in length, each with one to three 
points, more often with one or two; segments 2 to 9 each com- 
pletely encircled anteriorly with spinose bands; segment 10 with 
band generally interrupted by a narrow space on dorsum; seg- 
ment 11 with bands reduced to two or three rows of smaller 
spines laterally, these never completely encircling segment; seg- 
ment 12 with spines confined to ventral and ventrolateral sur- 
faces; ventral and lateral fusiform areas as in first instar; seg- 
ment 11 completely encircled posteriorly by a spinose band of 
about three rows of smaller anteriorly recurved spines; seg- 
ment 10 with irregular ventral and lateral rows, and a few 
scattered spines which may extend to the dorsal surface but 
not arranged to form a complete band; sometimes a few scat- 
tered lateral spines on segments 9 and 8 and a few ventrally on 
segments 7 and 6. Anterior spiracles paired, small, fan-shaped, 
one situated on each side near base of segment 2, generally 
with seven to nine fingerlike processes or branches; posterior 
