172 THE CANADIAN ENTOMOLOGIST. 



thicker ; 3rd shortest, others slightly widening towards tip ; 9th broadly 

 fusiform and longer than joints 6, 7 and 8 combined ; thorax about twice 

 as long as broad, microscopically punctate and with a slight brassy tinge 

 and sparsely pubescent ; collare hardly visible ; praescutum much broader 

 than long, convex, occupying nearly the whole mesothorax, scuti small, 

 triangular and purplish : scutellum rather large, convex, triangular, tinged 

 with brassy and with the basal margin purplish ; pleurae large, convex, 

 smooth and shining ; abdomen very short, sessile, flattened and triangular 

 when seen from above ; legs — coxce brownish, femora and more than half 

 of the tibiae brownish yellow, tip of femora and balance of tibiae and feet 

 honey yellow, hind legs with rather long tibial spur ; wings hyaline, iri- 

 descent, with only a short costa and stigmal vein, reaching to one-third the 

 length of wing. 



$ . Length .04 inch. Head purplish, vertex and face brassy, micro- 

 scopically punctate, with a few larger punctures scattered in front of 

 ocelli ; antennae 8-jointed, filiform, scape shorter than in $ and with the 

 joints irregular and covered with long hairs ; callare, unlike the female, is 

 transverse quadrate"; scutellum triangular with a brassy tinge and the 

 edges rounded ; abdomen longer than in female, blackish. 



Varieties of the male occur with the head, thorax and scutellum as in 

 the female, with an attenuated, transverse collare and with 9-jointed 

 antennae ; also with coarse punctures on the face and along the margin of 

 the eyes, and with the middle pair of femora yellowish. 



These varieties are important as showing how certain species of Chal- 

 cid flies are liable to vary in coloration and structure, even those bred 

 from the same brood. 



Described from 18 females and 8 males; 13 females and 5 males raised 

 from one larva, and 3 males and 5 females raised from another larva of 

 Syrphus 4-maculatus Ashmead, in November, 1 880. 



This species I place in the genus Pteromalus provisionally, for the 

 reason that the description was made from dry specimens and the antennae 

 in the ^ and the structure of the abdomen of both sexes was too much 

 shrunken to make a critical examination. 



