42 ENTOMOLOGICAL SOCIETY 



growth is attained late in the fall or in early winter, after 

 which the larva remains unchanged until shortly before the 

 appearance of the fly. Examination in June and July showed 

 no alteration in the larva. The fly must escape from the 

 tough bur with difficulty, and probably only succeeds when 

 the latter is softened by moisture or is opened by the germina 

 tion of the adjacent uninjured seed. It is probably by the 

 latter means chiefly that the fly effects its escape, and this 

 affords an explanation of the fact noted that the parent insect 

 oviposits in but one of the two seeds contained in a bur. 



The larva (Fig. i, b) is apparently i3-jointed, and when full- 

 grown is about 5 mm. long by 2 mm. wide, and is consider 

 ably flattened. The general color is light straw-yellow and 



FIG. 2. Trypeta tzqualis : female (original). 



the surface of the body is smooth and shining. The first seg 

 ment is plate-like, with radiating ridges, which form the central 

 oval opening, as shown at Fig. i, b ; the edges of the radiating 

 ridges are dark brown and the oral opening is almost black. 

 The thoracic stigmata are 8-branched and are situated in 

 oblong excavations at the upper (dorsal) corners of the plate. 

 A dark area surrounds the stigmata. The character of the 

 anal stigmata is shown in the illustration. The anal opening 

 is apparently on the nth segment. All the larvae examined, 

 including those collected early in the fall and apparently not 

 full-grown, had the general form indicated in the description 

 which, however, seems to be half-way between the larval 

 and pupal state as known in allied flies. 



The mature insect, the female of which is represented at 

 Fig. 2, is pale yellowish in color with whitish pile and bristles 



