Stratiomyiidae. 33 



1. O. trilineata Fabr. 



1781. Stratiomys, Fabr. Spec. Ins. Il, 418, 9. — 184.2. Zett. Dipt. 

 Scand. I, 142, 2. — 1857. Loew, Berl. Ent. Zeitsclir. I, 22. — 1862. 

 Schin. F. A. I. 9. — 1903. Kat. palaarkt. Dipt. II, 15. 



Male. Eyes bare, the facets in tlie lower tliird smaller tlian above: 

 the eyes greenish with a brownish red band on the dividing line between 

 the large and small facets. Vertex black, yellow behind the ocelli. 

 Frontal triangle and face greenish yellow, at the inner eye-margin a 

 dark stripe, hidden under whitish hairs; yowls and occiput black. 

 Antennæ reddish yellow, sometinies a little darker towards the apex. 

 Thorax green or greenish yellow with three black stripes connected 

 behind; scutellum green, the two spines black at the tips, postscutelluni 

 black; on the side of the thorax the green colour reaches somewhat 

 down the pleura, the sterna are black; below the pteropleuron there 

 is a somewhat clubshaped, oblique, green spot in the black coloured 

 part. All tlie thorax is clothed with white, shining pubescence, whicli 

 is yellowish on the median dorsal line. Abdomen green or greenish 

 yellow with tliree transverse, black spots, all being somewhat curved 

 and concave in front, connected on the sides with each other in such 

 a way that two transverse green spots are included, one on the second. 

 the other on the third segment ; the hind margins of the segments 

 are black ; sometimes the spots are separate and only concave in front. 

 Venter green or yellowish green. Legs all yellow. Wings hyaline, the 

 anterior veins yellow, the stigma very slightly yellowish. Halteres green 

 with a dark yellowish peduncle. 



ig. 15. Wing of O. trilineata. 



Female. Eyes greenish with a brownish red band in the middle, 

 not reaching the posterior margin. Front yellow or green with an 

 impressed, black middle line and narrowly black at the eye-margins; 

 vertex with a black, transverse band. Face white haired at the sides, 

 orbita yellow or green ; the back of the head black. The rest as in the male. 



Length 5 — 6 mm. 



The larva is greyish brown with some darker spots or stripes on 

 the segments, more or less longitudinally arranged; it has a length of 

 fully lu mm. 



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