196 Bulletin 176. 



mentioned is nndonbtedly Bracon nigropiotus Riley, but that tlie 

 Mic7'ogaster cannot be found. 



In 1889, Popenoe recorded (The IndustriaHst, June 8, 1889, XIV, 

 153) that " specimens of the pnpse and larvse of the peach-tree borer 

 collected in the College orchard, were inclosed in a breeding-jar 

 which now, a few days after the collection, is alive with specimens 

 of the two sexes of a honey -yellow Braconid fly, measuring in the 

 female about one inch, in the male about one-half as large. From 

 the abundance of this parasite in the jar where the dozen larvae and 

 pupae were confined, it may be inferred to be a common insect in 

 this locality." 



We have reared two other kinds of these little parasitic enemies. 

 On June 11th, 1896, we found in its cocoon a dead peach-tree borer. 

 A minute insect was seen to dart away from the cocoon, and we 

 found many long, narrow, white eggs laid near one end of the dead 

 borer. 



By June 16th, there had hatched from these eggs small, white, 

 maggot-like creatures which had evidently been feeding on the dead 

 body of the borer for a day or two. Tiiree days later the maggots 

 or grubs had entirely devoured the dead borer and had spun cocoons 

 around themselves both on the inside and on the outside of the 

 borers' cocoon. On June 29th and July -Ith, the adult parasites 

 issued from these little cocoons. Dr. L. O. Howard kindly deter- 

 mined them as BraGon mellitor Say. AVe bred these little Bra- 

 conids from two different specimens of the peach-tree borer, both of 

 which were dead when found. Is it possible that the Braconid fly 

 kills its victim before lajiing its eggs near the body, or does it attack 

 only those borers which have died from other causes? It is appar- 

 ently not an internal parasite of the peach-tree borer as we saw its 

 grubs feed only externally upon the dead bodies of the borers. In 

 July, 1898, we also bred the same Braconid from the cocoon of a 

 peach-tree borer which we found packed full of the cocoons of this 

 little enemy. 



About August 1st, 1899, we examined some plum trees at Geneva, 

 N. Y., and found four cocoons of the peach-tree borer. From two 

 of these there emerged a male and a female moth of the borer, but 

 from the other two cocoons we reared two large parasitic flies. One 



