22 BULLETIN 166, U. 8. DEPARTMENT OF AGRICULTURE. 
Papilio polyxenes Fab., Diacrisia virginica Fab., Deilephila gallit 
Rott., Deidamia inscriptum Harris, Callosamia promethea Drury, 
and an unidentified geometrid. In all of these cases the parasites 
passed the winter as larvee, emerging and pupating in the spring. 
No doubt when the host material lately in hibernation at the labo- 
ratory is fully examined the list of hosts in which Compsilura passes 
the winter will be materially increased. A single record of hiberna- 
tion was noted in a chrysalid of Pontia rapae that was kept inside 
during the winter, the Compsilura emerging January 18, 1915. 
While it would seem that this host is ideal for the hibernation of 
Compsilura, in no other case has the parasite been recorded as pass- 
ing the winter in it, although several thousand chrysalids of Pontia 
rapae have been collected from localities where Compsilura has been 
recovered in the fall and placed in hibernating quarters, 
Attempts which have been made to carry Compsilura through the 
winter in the adult and pupa stages, under laboratory conditions, 
have proved unsuccessful. In the early fall of 1916 a number of 
puparia were divided into two lots, one of which was placed in an 
ordinary glass vial and the other in a box of leaf mold and loam. 
Both lots were then put in an ice chest where the temperature varied 
from 40° to 42° F., and where the humidity was high and con- 
stant. A month later some of the puparia were taken from the vial 
and opened, disclosing well-developed, healthy nymphs. A few were 
opened from time to time until November 15, when the last were 
found dead. The last puparia found alive had been confined in the 
ice chest for 49 days, and it would appear that under natural condi- 
tions the puparia might hibernate, although attempts made in this 
direction have failed. 
In Bulletin 91 of the Bureau of Entomology, published in 1910, 
is found the only plausible explanation of the failure of Compsilura 
to hibernate within the overwintering brown-tail moth larve. On 
pages 219 and 220 is the following paragraph: 
Larve, which are almost certainly Compsilura concinnata, have been occa- 
sionally found in living brown-tail moth caterpillars during the winter months. 
It is presumed if these larve were able to mature under these circumstances, 
that they would have been reared before now from some among the hundreds ot 
thousands of brown-tail caterpillars which have been carried through their 
first three or four spring stages in the laboratory. None having been reared 
under these circumstances, the only logical conclusion is that they start into 
activity so early and develop so rapidly as to cause the death of the host before 
they are sufficiently advanced to pupate successfully. 
This, no doubt, is true, for the writer conducted experiments un- 
der ideal conditions for the hibernation of Compsilura, if this were 
possible, in hibernating brown-tail moth larve. From several places 
where Compsilura was prevalent during the summers of 1914 and 
1915, hibernating webs of brown-tail moth larvee were collected dur- 
Oo ERE) a EY Onn re Be ene art 
