242 MAINS AGRICULTURAL EXPERIMENT STATION. 1916. 



the cross-bands are attenuated and curved forward so as to reach the 

 anterior margin of the segment. The band on the fourth segment 

 also touches its anterior margin in the middle, while that on the third 

 is more remote from the anterior margin; the black interval between 

 the bands is twice as broad as the bands. The fourth and fifth seg- 

 ments have yellow posterior margins, the fifth usually with two yellow 

 spots on each side at the anterior margin. 



Male. "Similar to the female but abdominal cross-bands broader, 

 the biconvexity on their hind side stronger, and the sinus in the middle 

 deeper; the gray spot on the cheeks under the eye often larger, some- 

 times occupying a considerable portion of the cheek; the brown ring 

 on the hind tibiae usually expanded so as to reach the tip of the tibiae. 

 The eyes (contiguous) are more distinctly pubescent, the front is beset 

 with yellow pollen except a narrow black space above the antennae." 



Syrphus nitens Zetterstedt. 



Syrphus nitens Ztt. D. Scand. ii. 712 ? , viii 3137 (Scaeva). 

 Verr. Ent. M. Mag. v. 193; Brit. Fl. Syrph. 377, figs. 295, 296. 



Larvae of this European species, hitherto not recorded for 

 North America, were found on the campus of the University 

 of Maine, July 23 to August 1.1. Some of them "were full 

 grown on the former date, others only about half -grown on the 

 latter date. They were taken among colonies of the Willow 

 Grove Plant-louse (Pterocomma flocculosa Weed) on the 

 branches of a willow tree. The aphids were very ravenously 

 devoured. One larva under normal conditions was observed to 

 destroy twenty-one of these large aphids in twenty minutes. 

 Si-x empty, and one inhabited puparia were found glued to the 

 small branches of the willow on July 26. The adult from this 

 puparium emerged July 31. One of the larvse collected July 

 26 pupated July 27 and emerged as adult ( 2 ) August 6. 

 Another pupated August 1 and emerged ( S ) August 12. The 

 duration in the pupa stage is therefore about 10 to 12 days. 



Besides extending the known distribution of this species, 

 this record is of particular interest because the larvse are the 

 only ones of the aphidophagous type I have seen in which the 

 spiracles on the posterior respiratory process are not straight 

 but remarkably convoluted (See Fig. 34- 5 and 4). 



Larva (Fig. 34-1, 2, 3, 4, 5). Length about 15 mm., width about 

 3 mm,, height about 2.5 mm. An unusually slender, elongate species 

 broadest about the eighth segment, but of nearly equal width from 

 segment seven to eleven. The twelfth is nearly a third narrower and 

 somewhat depressed, the posterior end squarish. Anterior to segment 



