8 BULLETIN 1028, U. S. DEPARTMENT OE AGRICULTURE, 
sickle-shaped mandibles (PL I. J), which are well fitted for tearing, 
are plainly seen, being- in motion much of the time, as the maggot 
feeds on the lymph and fat bodies of its host. They are 0.08 mm. 
long, are chitinized throughout, but more heavily- so at the tips, and 
form a good character for distinguishing this stage from the follow- 
ing ones. The body is made up of ten segments at this period, but 
later has eleven after the tenth segment divides. On the dorsum the 
maggot has a systematic arrangement of short, rather stiff, back- 
ward pointing spines. The spines are located as follows : Two each 
on the second and third segments, four on the fourth segment, six 
each on the fifth to ninth segments inclusive, and eight on the tenth 
segment. It seems likely that these spine- assist the maggot in 
working itstway to the caudal end of the host. 
The anal vesicle, which is common to the microgasterine larva?. 
is prominent and the caudal horn is seen just beneath the evaginated 
anal vesicle. 
As the larva matures, the heart, nervous system, and silk glands 
can be distinguished, but no evidence of the tracheal system is ap- 
parent. 
When ready to molt the larva has increased in length to nearly 
2 mm. and the body has widened in proportion, except the head. 
which remains about the same width throughout the stage. 
The larva remains in this stage from two to three days in the 
spring generation and from six to eight days in the summer genera- 
tion. 
SECOND-STAGE LABYA. 
In molting the head skin of the first-stage maggot is split off and 
is occasionally found in the body cavity of the host, closely associated 
with the cephalic region of the second-stage larva. The remainder 
of the molt skin is worked back to the last body segment (PL I. G 
at M). 
The second-stage maggot is usually found dorsally in the caudal 
end of the host in the body cavity, its head toward the posterior end 
of the caterpillar and its body resting longitudinally. When first 
molted it measures about 2.75 mm. in length and 0.55 mm. in width, 
the head and body being approximately the same width. 
In contrast to the first-stage maggot the body is entirely destitute 
of spines and the mouthparts are poorly developed. The mandibles 
(PI. I. K) are not fitted for tearing or biting, but are soft, fleshy 
forms without chitin and are very difficult to locate. 
The anal vesicle is still present and is more prominent than in the 
previous stage (PI. I. G at A). The caudal horn is present but has 
not grown with the developing maggot and appears very small in 
comparison with the size of the larva (PI. I. G at P). 
