June, 191:^.] Life- Histories of Syrphidae IV. 537 



The duration in the pupal stage varied in captivity from 3.5 to 

 5.5 days in the case of those taken from persimmon in the spring, 

 while in Autumn in specimens from cabbage the duration in the 

 pupal stage was in some cases as much as 10 days. 



These pupa^ are fastened by a viscid substance secreted by the 

 anal glands of the larva which, in drying, glues them to various parts 

 of the host-plant of the aphids among which they live. They 

 attach to the flowers and in the curls of the leaves of persimmon, 

 in leaf -axils, or flower spikes of Rum ex and on cabbage among the 

 outer leaves. In jars they attach to the cloth cover, the glass, or 

 to leaves enclosed, apparently with no discretion. 



The body shortens and thickens and the larval skin inflates 

 and hardens in the usual manner. Within this puparium profound 

 changes take place which culminate in the completely formed 

 nymph, which has only to spread its wings and harden, after 

 bursting out of the pupa case, to fonn the perfect fly. 



Adult. 



Description after Williston, Synop. N. A. Syrph., 9G, 1886. 

 (See Fig. 64.) " cf 9 . Length, 6 to 7 mm. Face yellow, often 

 with a bluish reflection, slightly brownish on the tubercle. Frontal 

 triangle yellow ; front in the female shining black on the vertex, con- 

 tinued as a broad stripe (broadest below) to the antennae; on the 

 sides the yellow of the face continues up along the eyes nearly to 

 the ocelli. Antenna? reddish-brown, blackish on the upper part 

 of the third joint. Thorax deep shining green, on the sides with 

 a 3'ellow stripe, reaching from the humeri to the suture, where it is 

 sharply truncate ; post-alar callosity also yellow. Scutellum wholly 

 light yellow, faintly reddish on the disk; pile black. Abdomen 

 black, or brown; first segment, except a slender transverse spot on 

 each side behind, yellow; second segment with a slender yellow 

 anterior fascia, and a broader one in the middle, about a third of 

 the width of the segment, straight and but slightly widened at the 

 sides ; third segment with a broad arcuate band, not quite touching 

 the posterior angles on the sides ; fourth segment with two slender 

 parallel stripes, leaving a slender black stripe between them, on 

 each side a broader, oblique, oval spot, touching, or narrowly 

 separated fron the anterior end of the yellow longitudinal stripe, 

 and reaching to the posterior angles; fifth segment similar, but 

 the side spots less oblique. Legs light yellow; last three joints of 

 all the tarsi, the hind tibise, except the base and a middle ring, and 

 a ring on outer part of hind femora, brownish. Wings hyaline, 

 veins black." 



