THE LEGUME POD MAGGOT. 
(Pegomya planipalpis Stein.) 
By James A. Hystop, 
Agent and Expert. 
GENERAL ACCOUNT. 
About the middle of July, 1909, a large number of larvee of Pegomya 
planipalpis Stein were found leaving the pods of lupines that had 
been placed in rearing cages. On the 28th two pup were found in 
one of the cages. Within the next few days many more larve left 
the pods and pupated. A number of these puparia placed in a glass 
vial during the autumn of 1910 were kept in the field laboratory all 
winter. May 11 of the following year the first adult emerged and 
from that date others emerged daily throughout the remainder of 
the month. By a number of experiments it was found that humidity 
greatly facilitated the emergence of these flies. 
These flies were first believed to be scavengers, feeding on the 
frass and decaying seed of the lupine and field peas in the wake of 
the legume pod moth. However, investigations in 1910 proved that 
the insect, though often found with Etiella, was quite capable of 
independently infesting seed pods and was itself an actual seed de- 
stroyer. Many pods were found to contain from one to three of these 
larvee. 
Dr. F. H. Chittenden,' of this bureau, notes this species as attacking 
radishes at San Francisco, Cal. 
The larve molt at least twice, as two pairs of pharyngeal hooks 
were found in a pod with one larva. Though several of these dipter- 
ous larvee were found in field-pea pods with the head capsules of 
larvee of the legume pod moth, we hardly believe this species to be 
parasitic, as larvee confined in small vials with pod-moth larve would 
not attack the latter. 
In cages with earth in the bottom the pupe were always to be 
found below the surface at distances ranging from 1 to 3 inches. The 
larve contract just before forming a puparium. The puparium is 
at first creamy yellow, turning brown at the ends first and finally 
becoming entirely ferruginous. A larva that contracted on the 
morning of July 31, 1911, assumed the usual puparium form by 9.30 
a.m. of the same day. It was still pale yellow, but by 2.30 p. m. it 
had become brownish at the ends and deep orange-yellow at the 
middle, while next morning the puparium was uniformly ferruginous 
brown. 

1 Bul. 66, Pt. VII, Bur..Ent., U. S. Dept. Agr., p. 95, 1909. 
