234 ERNEST A. BACK. 



vertical. Thorax well arched, with bristles above base of 

 wings and on the posterior callosities; scutellum with bristles, 

 sometimes very short. Abdomen robust, strongly convex, 

 and but little tapering; lateral forceps of the male genitalia 

 alone prominent and widely separated, thus giving the end of 

 the male abdomen an " open" or " broken" appearance. Legs 

 robust, normal, the fore tibiae without a terminal claw-like 

 spur. Submarginal and posterior cells widely open; anal cell 

 closed at the margin or narrowly open. 

 Type. — Dasypogon aurulentus Fabricius. 



SYNOPSIS OF SPECIES. 



1. Terminal segment of antennae fusiform; wings pure hyaline; body 



wholly golden pruinose except the thoracic stripes and a 

 triangular spot at base of abdominal segments. 



aurulentus. 



Terminal segment of antennae nearly or quite linear; wings usually 



brownish-yellow 2. 



2. All the abdominal segments with a golden posterior cross-band. ...3. 

 Only segments 1-5 with a grayish posterior cross-band; pleurae 



wholly grayish pruinose ? dimidiatus. 



3. Pleuras black, with golden spots cruciatus. 



Pleurae thickly light-yellow pruinose nigripes. 



Ceraturgus aurulentus, 



Dasypogon aurulentus Fabricus, Syst. Antl., 166, 1805. 

 Dasypogon aurulentus Wiedemann, Dipt. Exot., 288, 1821; An- 



alecta Ent., 12, 1824; Auss. Zw., 414; pi. V, fig. 5, 1828. 

 Ceraturgus aurulentus Macquart, Hist. Nat. Dipt., I, 289; pi. 



VII, fig. 4, 1834. 



Ceraturgus aurulentus Brauer, Wein, Ent. Zeit., I, 56, 1883. 



Ceraturgus aurulentus Johnson, Psyche, X, III; 1903 (fig. of 



antenna) . 



9- — Length 8-9 mm. — Black, everywhere golden pruinose except 



the stripes of the thoracic dorsum and the proximal portions of the 



abdominal segments. Antennas apparently five-jointed; first segment 



cylindrical; second, a little compressed and incrassate at tip; first 



and second segments subequal; third segment longer than the first 



two taken together; fourth very short; fifth, compressed, fusiform; 



the fourth and fifth densely pubescent. Stripes of thoracic dorsum 



very broad; the median stripe extending from the pronotum nearly 



to the scutellum; the lateral stripes bisected by a golden pruinose 



line along the transverse suture and drawn out to a point behind; 



they are separated throughout their length from the median stripe by 



