302 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



°E. orbitalis Cresson. 



Female : length 6 mm. 

 °E. flaxicoxae Cresson. 



Female and male : length 5 mm. 

 *E. censors Cresson. 



Female : length 6 mm. 



T^pe locality: Connecticut (E. N.). 



Syrphoctonus Foerster. 

 *S. agilis (Cresson). Bassus agilis Cresson. 



Male : length 4 mm. ; mostly black ; face beneath antennae, 

 lower part of cheeks, scape beneath, a large mark on each side of 

 the mesothorax, tegulse, a spot before on the scutels, pleurae, 

 except a large mark beneath the wings, base of fore and mid legs, 

 and a basal spot on each side of the third dorsal abdominal seg- 

 ment, yellow ; antennae stramineous beneath ; wings hyaline, veins 

 and stigma brown, areolet wanting ; legs pale honey-yellow, hind 

 tibiae and tarsi blackish, bases of former more or less, and their 

 spurs, pale ; venter of abdomen more or less pale. 



Type locality: New Haven, 15 July, 1904 (W. E. B.). 



Promethes Foerster. 

 °P. costalis (Provancher). Bassus costalis Provancher. 

 Female : length 5 mm. ; mostly black ; mouth, palpi, tegulae, a 

 mark in front of tegulae, a line on mesopleurae, costa, the coxae, 

 and trochanters, pale yellow; hind coxae more or less reddish 

 beneath. 



Diplazon (Nees) Gravenhorst. 

 Bassus Authors, not Fabricius. 



*D. frontalis (Cresson). 



Female : length 5 mm. ; mostly black ; spot on face, sometimes 

 the margins of the clypeus, a spot on the mandibles, palpi, tegulae, 

 a spot or cuneiform mark in front of the tegulae, a short line be- 

 neath the tegulae on the mesopleurae, and a spot at tip of the 

 scutel, white ; legs honey-yellow, tips of hind femora, their tibiae, 

 except bases, which are pale, and their tarsi, black ; wings hyaline ; 

 veins brown, areolet wanting. 



