296 



TRANS. ST. LOUIS ACAD. SCIENCE. 



Notes on North American Microgasters, with 



descriptions of New Species. 



Bv C. V. Riley, M.A., Ph.D. 



[Read Feb. 7, iSSi.] 



Fig. 1. — Apanteles aletive: a, female liy; b, outline of head of larva in position to- 

 siiow the ehitinized parts of the mouth, the mandibles not visible, being withdrawn; 

 c, one of its mandibles as seen within the head of a mounted specimen; d, cocoon; e, 

 joint of antenna — all enlarged: nat. size of a and rf in hair-line. (Riley, del.) 



The insects of this group are among the most common parasites 

 of the various caterpillars injurious to vegetation. They are, there- 

 fore, among the more important of the farmer's insect friends. Yet 

 they have hitherto been but httle studied in this country ; for, aside 

 from the eight species described by Say, w^e have only one species 

 described by Fitch, one by Walsh, one by Packard, two by my- 

 self, and two Texan species by Cresson, while notices of the habits 

 of only a few of these have been published. I have during the past 

 fifteen years, in rearing Lepidoptera, obtained quite a number of 

 species, some of which have been sent to Dr. A. S. Packard, Jr., 

 of Providence, R, I., but most of which have been referred to Mr. 

 E. T. Cresson of Philadelphia. Dr. Packard proposes shortly to 

 describe several species, and more particularly those affecting but- 

 terfly larvae, while Mr. Cresson is at the present time working up 



