19 
suddenly about and then quieted again; the little tormentor meanwhile 
sitting perfectly composed on the spot where she first settled. Pres¬ 
ently another thrust was made, followed by further uneasjr move¬ 
ments of the larva, and in this manner, in the course of a very few 
minutes, quite a number of eggs were deposited. The caterpillar did 
not seem to he conscious of the cause of its troubles, nor, indeed, of the 
presence of its enemy, excepting when the thursts with the ovipositor 
were made. On drawing a little nearer for the purpose of better ob¬ 
serving this interesting operation, the tiny creature took alarm and 
flew off. Further examination revealed the presence of several more 
of these little friends, busily searching for further specimens to ope¬ 
rate on. The eggs deposited soon hatch into little grubs, which even¬ 
tually devour the body of their victim, and after it has entered the 
chrysilis state, eat small holes in the* chrysalis, and thus make their es¬ 
cape.” 
The number of these maggots which live in one chrysalis is often 
very great, sometimes amounting, according to Curtis, to as many as 
two or three hundred in the pupa of P. brassicce which is larger than 
that of P. rupee. 
It is proper to remark here that according to Mr. Meldola ( Pro . 
Ent. iSoc. Loud , 1876 —XXXV) it is Pteromalus imbutus that is para¬ 
sitic on P. rupee. But that the species which infests P. raprje in this 
country is Pt. pvparum has been positively determined by Dr. Pack¬ 
ard who has compared specimens obtained in this country with Euro-, 
pean specimens. He states that the usual number found in a single 
chrysalis of P. rupee is from fifteen to thirty which accords with my 
observations; but Mr, Couper (Can. Ent. VI. 37) states that he has 
counted as many as ninety-five in one chrysalis. 
In the pupa shells which I have opened, some of which are now 
before me, I find that all the parasites have not escaped, but in each 
there are more or less dead. As these have passed from the pupa 
state it is evident they have not been attacked by a second parasite; 
the question then arises, Have they failed to perfect their organiza¬ 
tion and acquire sufficient strength to cut their way out for want of 
sufficient food? Judging from Mr. Curtis’ observations this would 
seem to be impossible, but we must bear in mind the fact that his 
statements apply to the larger chrysalis of Pierls brassicee. 
These little parasites, as may be inferred from what has been stated, 
undergo their transformations in the body of the chrysalis or pupa; 
the perfect flies coming out of the summer brood in about two weeks; 
but those in the fall brood do not make their appearance until the 
following spring. 
Their multiplication is so rapid that when they make their appear¬ 
ance early in the season where the butterflies prevail, it will be found 
that the larger portion of the fall pupae are parasitized. Dr. Packard 
states, that out of one hundred and ten chrysalids handed him by 
Mr. Pucnam in September, (1876) all but two were infested. The in¬ 
fested specimens I have examined were obtained chiefly in the north¬ 
ern part of the State, and selected because they were parasitized, 
hence I am unable to state the proportion. 
Although the parasite has made its appearance in my immediate 
section, it came too late to affect any but the last brood of the past 
season. 
