238 



THE CANADIAN ENTOMOLOGIST 



Length 6 to 7 mm. ; length of wing 5 to 5.5 mm. 



Described from 12 specimens taken in 1918 at El Centre and Alhambra, 



Cal. 



Adult male (after Williston's quotation of Osten Sacken) (2). 



". . . Length 7 mm. Face, including the frontal triangle, pale yellow, 

 slightly opalescent, a bluish black stripe extends from the oral edge to the 

 antennse, forming a semicircle above them. Antenna reddish, third segment 

 brown along the upper edge, vertex black. Thorax bright m.etallic green, a 

 pale yellow stripe on each side between the humerus and the root of the wings; 

 ante-scutellar (post-alar) callosity yellowish; scutellum of a saturate yellow, 

 the extreme corners dark; halteres with yellow knobs. First abdominal 

 segment metallic greenish black, its extreme anterior margin only 

 yellow; the rest of the abdomen black, opaque; an interrupted yellow 

 cross-band on the second segment equal to about one-third the segment 

 in breadth; a somewhat broader, slightly arched, and not interrupted yellow 

 cross- band on the third segment; on the fourth, two narrow, parallel, longitudinal 

 lines in the middle and an obliquely placed, large, oval spot on each side of them, 

 yellow; the narrow fifth segment shows a yellow picture, somewhat resembling 

 that of the fourth segment. Legs yellow; tip of tarsi brownish; hind femora 

 with a brown ring before the tip; hind tibiae with two such rings, one before the 

 middle, the other before the tip; hind tarsi brown, except the under side of the 

 first joint. Wings hyaline; stigma brownish yellow." 



Fig. 31. A, B. — Allograpla obliqua, female, dorsum of abdomen 

 and front view of head. C, D. — Allograpla fracla, female, 

 dorsum of abdomen and front view of head. 



Osten Sacken (3) described the species from a single male collected at 

 Santa Monica, Cal., in 1876. There are before the writer 22 males from southern 

 California; of these 20 have the cross-band of the second segment constricted 

 in the middle and 2 have it interrupted, so that normally this band is not divided 

 as in the type specimen. Also in these 22 males the coloration of the first 

 abdominal segment varies as in the females, some having considerably more 

 than the "extreme anterior margin only" yellow. In the males the cross-band 

 of the third abdominal segment is on the average broader, and the oblique 

 spots of the fourth segment larger than in the females. 



Williston (2) indicated the differences between Allograpla ohliqua and A. 

 fracta to consist in the faint brownish facial stripe and yellow first abdominal 



