22 
The larvre are rather slender, ranging from 6 to 10 mm. in length, 
few, however, exceeding 7 or 8 mm. They have apparently 18 feet — 
G thoracic and JL2 abdominal — the anal pair of abdominal feet being rudi- 
mentary. Up to maturity, the body is yellowish white, the head res- 
inous or brownish, tips of mandibles darker, and the eyes, with narrow 
border, dark brown, almost black. The last joint of the thoracic legs 
and the claws are resinous. Just before abandoning their galls the 
larva' undergo the final molt, 1 assuming a body tint of a dull grayish 
purple, the head becoming by contrast and in fact of a lighter brown. 
This obscure coloring is unquestionably a most valuable safeguard 
against discovery by predaceous insects or birds during the wandering 
of the helpless, delicate larva in search of hibernating quarters. The 
cocoon is ovate, of silken threads, more or less agglutinated, thin, and 
delicate. The life history of Pontania pisum Walsh, illustrated in figure 
7 (p. 33), is typical of the genus. 
The fact noted above, of the habit of the larvaB of entering wood, 
pith, or other like dry material to pupate, probably explains records 
made by Walsh and others of certain species which have been desig- 
nated as inqnilinous, either in the galls of other Nematines or in 
cecidomyiid galls. I am convinced thai these records are all doubtful, 
and that the larvae of these insects, on abandoning their own galls, had 
simply entered the others lor hibernation. The fact that a species had 
been reared from a cecidomyiid gall, for instance, was taken as suf- 
ficient evidence that it Mas inqnilinous, and a new species was erected. 
This is illustrated in the case of Nematus hospes Walsh, which is said 
by the describer to be " absolutely indistinguishable from the normal 
type, the gall-making Nematus s. pomum." This species was reared 
from a gall of Cecidomyia s. strobiloides O. S. It is unquestionably 
identical with pomum, and in fact I have recently received from Cor- 
nell University two specimens undoubtedly of ponnim, labeled as hav- 
ing been reared from the cecidomyiid gall referred to. The same is 
true of Nematus inquilinus Walsh, which was reared from the gall of 
Cecidomyia rhodoides Walsh. This species is identical with Pontania 
desmodioides Walsh, and the larva had merely entered the cecidomyiid 
gall to hibernate. 2 
In going over the material of the Entomological Society of Phila- 
delphia, the accumulations of the United States National Museum, the 
1 See "Final Moulting of Tentlirodiuid LarvaB/' Proc. Ent. Soc. Wash., vol. n, 
p. 115. 
^Nematus mendicus Walsh, which was reared from deserted galls of pomum and 
from the leaf galls of Cecidomyia brassicoides Walsh, helongs to the genus Ptcronus. 
The larva'- apparently entered the galls in question to hihernate, and, with very 
little doubt, developed exposed on the leaves, as is the case with the other species 
of I'teronus living on willow. Nematus fur Walsh, which was bred from the gall of 
Cecidomyia batatas Walsh, seems also not to be a Pontania. The type specimen can 
not be found, but on the authority of Norton it is probably identical with Nematus 
luteotergum, which would bring it within the genus Amauronematus. 
