104 REPOET 4, XJNITED STATES ENTOMOLOGICAL COMMISSION. 



Our experience accords with that of Mr. Hubbard, though the number 

 infesting a single egg is not invariably two. We have often obtained 

 but one from a single egg, and, according to Mr. Schwarz's experience, 

 three may exceptionally be obtained. As will have been gathered from 

 Mr. Hubbard's notes quoted above, the Trichogramma has been raised 

 from the eggs of HeliotMs armigera — the Boll- Worm moth. It has also 

 been reared from the eggs of Laj^hygma frugiperda, the Grass-Worm 

 moth, and from the eggs of an unknown Tortricid on orange. We have 

 also found a minute yellow parasite of somewhat similar general ap- 

 pearance and easily mistaken for it, but in reality very distinct when 

 carefully examined, infesting the larva and the pupa of an undescribed 

 Aleurodes that is common on cotton, two or more flies issuing from each 

 Aleurodes.^^" 



Infesting and issuing from the Worm. — The Cotton- worm Microgaster.— 

 This species, described by us as Apanteles aletice,* has been very fre- 

 quently found during the past few seasons in Florida, Alabama, and 

 Texas.^^ The egg is laid in the posterior portion of the body of partly- 

 grown larvae of Aletia (never in very young or full-grown worms). It 

 is a solitary parasite, only one specimen infesting a single Cotton Worm. 

 We quote the observations upon the species made by Mr. Hubbard, 

 who has watched it more carefully thau any of the other agents : "Late 

 in August, while the worms of the fifth brood were in process of devel- 

 opment, I discovered on the underside of lower leaves of cotton and 

 upon grass growing under the shade of the oak tree at the center of 

 this brood, a number of little oval cocoons of white, flossy silk, about 4°^°^ 

 (0.16 inch) long. Close beside these dangled the dead body of a young 

 cotton worm, suspended from the leaf or from the cocoon by a thread 

 of silk. In about a week each cocoon produced a Microgaster (most 

 of my notes relating to this parasite having been lost, I am unable 

 to give the exact j^eriods in which it undergoes its transformations). 

 Subsequently I observed the larva, naked and memberless, its body 

 tinged with green by the juices of its prey, in the act of spinning its 

 cocoon. The larva forms the exterior by throwing out loops of ropy 

 fluid which, under a lens, are seen to become rigid as they fall, and to 

 harden rapidly, forming rather a coarse strand of white silk, which is 

 often beautifully furred. These loops are piled one upon another and 

 the walls of the cocoon rise rapidly until they meet overhead. The in- 

 side is lined in the manner usual with lepidopterous larvae until the 

 whole has become opaque. The process of spinning occupies about two 

 hours' time. After August 20, nearly all the young larvae of Aletia col- 

 lected were found to contain this parasite, which kills and emerges 

 from the worms when they have attained a quarter of their full growth. 

 In quitting its host the i)arasite maintains its connection with the body 



* Transactions of the Academy of Science of St. Lonis, Vol. 4, U^o. 2. 



