34° , The Ohio Naturalist. [Vol. XI, No. 7, 



Length 9.5-10 mm., width 4.5-5 mm., height about 4.5 mm. 

 Color, Roman sepia, a little darker than the larva. The puparium 

 is broadest a little back of the sixth larval segment, is nicely 

 rounded in front, and tapers gradually to the last segment which 

 remains somewhat flattened, especially at the sides. The cover- 

 ing of small black bristles is retained and the black conical prom- 

 inences become even more cons])icuous owing to the inflation 

 (Figs. (), 7). The posterior breathing appendages are retained. 



The date of pupation was about the middle of October. Indoors 

 the duration in the pupal stage was about 20 days. 



I have made no observations which would indicate that the 

 larvae crawl far before changing to the pupae. I have found 

 pupae on the under sides of the horizontal branches of the Syca- 

 more not far from the colonies of plant lice among which they fed. 



The shining brown color together with the black, s]Diny, 

 conical projections on the dorsal side give to the pupa of Didea 

 fuscipes a characteristic appearance easily distinguished from 

 that of the other Syrphidae I have seen. The pupae are protected 

 by the indurated puparium and somewhat by the sheltered posi- 

 tion on the bark taken up by the larvae. 



I have found the pupa late in November and it is probable 

 that the fly passes the winter in this stage. 



The adults have been taken from the middle of May to the 

 last of September. I have studied only the autumn generation 

 of larvae. 



The adults emerge by bursting off a circular lid of the pupa 

 case (Fig. 7). This is accomplished by expansion of the lower 

 part of the face 



ADULT. 



9 , cf. Length 11-15 mm. 



Description, sHghtly modified from Williston. Bull. U. S. 

 Nat. Mus., No. 31, 89 (ISS(l). Face yellow, with a small 

 elongate brownish si:)ot on the tubercle. Front yellow, with 

 two brownish spots abo\'e the antennae, or, in the female, 

 with an inverted V-shaped brown stripe connected with the 

 black of the upper part of the front. Eyes bare. Orbits 

 thickly yellowish pollinose, posteriorly with a fringe of yellowish- 

 whitish pile. Antennae black, the third joint at the base some- 

 times reddish, elongate oval, obtusely pointed at the tip; arista 

 reddish. Thorax shining greenish black, on the meso-, ptero-, and 

 sterno-pleurae yellow, thickly covered with similar colored pollen 

 and pile. Scuttelum light yellow, translucent. Wings grayish 

 hyaline, the base before the humeral cross- vein ■ and the stigma 

 brown; the remainder of the sub-costal cell and the costal cell 

 may be brownish ; third vein rather deeply curved near the middle 

 of the first posterior cell. Legs brown, the posterior tibiae and all 

 the tarsi blackish; sometimes the legs are luteous, the base of 



