313 



When full grown the larva is about 5 millimetres long by 2 millime- 

 tres wide, is considerably flattened, and is light yellowish or resinous 

 in color. All of the many specimens examined, some of which were 

 apparently immature, had the 

 appearance given in the illus- 

 tration, which, however, seems 

 to approach the contracted con- 

 dition of the puparium. The 

 larva has never been found to 

 occur in more than one of the 

 two seeds normally contained 

 in the Xanthium bur. 



It reaches full growth in 

 September or October, and 

 passes the winter in the bur 

 unchanged, as represented at 

 rig.27fl. In July the trausfoi - 

 mation to puparium and adult 

 takes place, the latter emerging 

 late in July or early in August, and doubtless effects its escape from 

 the tough pod by the opening of the latter incident to the germination 

 of the uninjured seed. The new burs are at this season green and 

 succulent, and can readily be pierced by the female in oviposition. 



The adult insect, the female of which is shown at Fig. 28, is uniformly 

 yellowish in color, and has the characteristic brownish maculation of 

 the wings indicated in the illustration. 



Fig. 28. — Trypeta cequalis. Female fly, enlarged 

 (original*. 



VARIATIONS IN THE BRACONID GENUS LYSIPHLEBUS. 



By D. W, COQUILLETT. 



In the proceedings of the U. S. National Museum, 1888, pages 664 to 

 669, Mr. W. H. Ashmead has published descriptions of twelve supposed 

 new species of Lysiphlebus, and makes mention of three other species, 

 all of which are included in a synoptical table of the North American 

 species. The types of four of these supposed new species were fur- 

 nished by myself, and before submitting them to Professor Eiley I care- 

 fully examined them, and reached the conclusion that they all belonged 

 to one and the same species. I was therefore not a little surprised to 

 learn that Mr. Ashmead had made four distinct species out of them. 

 After perusing the above paper, for a copy of which I am indebted to its 

 energetic author, I determined to investigate the subject still further; 

 accordingly, on the 14th of December, 1889, I collected a colony of par- 

 asitized aphids from a single bush of Baccharis viminalis and confined 

 them in one of my breeding cages. Between December 18 and January 4 

 121 specimens of Lysiphlebus had issued; of which number 57 were 



