PARASITES OF ALETIA. 
101 
during the past live years that the Boll Worm (Hcliothis armigcra) when 
approaching full growth develops a strong, carnivorous appetite, and 
not only destroys the 
smaller worms of its own 
species, but also enters 
the loose cocoon of the 
Cotton Worm and feeds 
upon the inclosed papa. 
There is good evidence 
that the Grass Worm 
( Laph ygma frugiperda ) 
occasionally eats the Cot- 
ton Worms, a fact which 
seems probable from the 
known habitS Of La- Pia. 20.—Libcllula trimmeulata. (After Snnl.orn.) 
phygma, and even the Aletia larva, like many other species of its order, 
when hard pressed, will develop cannibal propensities. 
PARASITES. 
Up to the time of the appearance of the first edition of this work in 
January, 1880, or rather up to the time of the appearance of a prelim- 
inary article by us in the Canadian Entomologist for September, 1879, no 
parasites of the Cotton Worm had been recorded, by name so as to be rec- 
ognized by entomologists, and the belief was qnite general that Aletia 
was entirely free from parasitic checks. This belief, as \\ <• have already 
seen, was used by Mr. Grote as an argument in favor of the arrival of 
Aletia fle novo from some foreign country whenever it appears with us. 
Tin; fact remains, however, that one of the most important of these par- 
asites had been mentioned without name by six writers at least, and 
that two tolerably good figures of the species had been published. In- 
deed, the very fact of the existence of such a parasite had been used by 
Dr. Gorham to found a theory similar to Air. Grote's, as we shall show 
under the head of u History of the literature." 
The following species have been discovered since we began this Cot- 
ton Worm investigation. The observations of the past two years have 
added four parasites to those published in the first edition of this work : 
Infesting and issuing from the egg: 
(1.) Trichogramma prctiosa Riley. 
Infesting and issuing from the worm (the parasitism of No. 5 doubtful) : 
(2.) ApantcJes alctiw Riley. 
(3.) Euplectrus comstoclii Howard. 
(4.) Sarcophaga sarraceniw Riley. 
(5.) Cyrtoneura stabnlans Fallen. 
(6.) Tachina aletia- Riley. 
(7.) Tachina f rater na Comstock. 
