THE LEGUME POD MOTH. 93 
covered, measured 1.2 mm. in length and was found just inside the 
pod at the terminus of a burrow which led from just in front of the 
egg through the calyx and pod wall. The hole through which the 
larva emerged from the eggshell was terminal, round, and very neatly 
cut. A few days later two eggs were found on the caleyces of field 
peas; these were brought into the insectary but failed to hatch. 
During late July and early August, 1911, larve in all stages of 
development, from very small specimens, evidently just hatched, to 
those which were mature and spinning cocoons, were found in both 
the pods of field peas and lupines. The larvee on first emerging are 
pale green or cream colored, the pronotal plate and head being 
entirely black or brown; with the first molt the pronotal plate assumes 
the characteristic pattern described elsewhere in this paper, but the 
body does not assume the rosy tint as described until nearly mature. 
The larve feed for about three weeks, only partly consuming the 
peas, as is seen in figure 32, destroying them as seed, besides greatly 
reducing their weight as stock feed. The pod always contains a mass 
of frass held to- 
gether by a loosely 
constructed web. 
The larva will 
leave one pod and 
enter another if 
the food supply is Fia@. 32.—The legume pod moth: Larva feeding in a pod of field pea. En 
exhausted, or if J larged. (Original. ) 
for any other reason the pod becomes uninhabitable. When mature, 
if the peas are still unharvested in the field, it emerges from the pods 
and enters the ground to pupate, or if the pods have been harvested 
it spins a tough silken cocoon in the nearest available sheltered place. 
Larve that become mature during the warm weather of early 
August, out of doors, or later under laboratory conditions, pupate 
immediately and emerge as adults in about six weeks. Adults have 
been obtained in our laboratory on August 5 and as late as August 28. 
Whether these lay eggs which pass the winter successfully, or whether 
they hibernate as adults, is still undetermined. Larve that reach 
maturity in late September, when the nights are cold, spin their 
cocoons and hibernate therein as larve, pupating in the spring and 
emerging at the time the earliest lupines are setting seed. 
On the lupines there are very probably two generations a year. 
The moths of the first generation, coming from hibernating larve, 
lay all their eggs on the lupines, as the field peas are just commencing 
to grow. The offspring of this generation mature late in July and, 
finding the field peas ripening, very naturally turn their attention 
to these large areas of suitable food as well as to their natural food, 
the later lupines. 
29993°—Bull. 95, pt. 6—12 


) 
“ 
