1928] 
Biological Notes on Nemeritis canescens 
125 
from young leafy shoots of the tree, Guazuma tomentosa Kth. 
So far as can be ascertained from collections of the adults only, 
it would thus appear that this is a highly polyphagous species. 
I found it at Soledad only during February and March, but 
Dr. Salt took it there on 20th June, and at San Nicolas (Habana) 
on 15th April. 
BIOLOGICAL NOTES ON NEMERITIS CANESCENS 
(GRAY.) (ICHNEUMONIDtE) . 
By P. W. Whiting, 
University of Pittsburg. 
On September 7, 1926 at Lowell, Massachusetts, in a grain 
and feed store heavily infested with Ephestia kuehniella Zeller 
and Plodia interpunctella Hb. there were observed a large number 
of females of Nemeritis canescens (Grav.) No males were to be 
found. 
Six of these wasps were set with Ephestia larvae and des- 
cendants were reared during the winter through six generations. 
Females only were produced totalling 3953. Since all of these 
except the 415 of the first generation were reared from bred 
virgins and since no males could be found among the numerous 
specimens in the store, the species appears to be almost or quite 
thelytokous. 
Dissection showed that many eggs may be laid within the 
tissues of one caterpillar although only one maggot develops. 
The caterpillar is not paralyzed but feeds and grows normally 
and usually spins a cocoon. Ordinarily the full-grown maggot 
ruptures the skin of the caterpillar and spins its own brownish 
cocoon within the white silken tube of the latter. Not in- 
frequently, however, the caterpillar is able to form a chrysalis in 
which case its chitinous covering left intact encloses the cocoon 
and pupa of the wasp. Adult wasps may be kept alive for 
several days if fed on honey and water. 
There have been bred from single females from five to 43 
offspring, but it is very likely that this number might be con- 
