370 APPENDIX. 



Head yellowish-testaceous ; orbits beneath and behind 

 dark cinereous ; vertex with an elevated, obtuse, dusky 

 line between the stemmata ; Mor^/cT ferruginous; anterior 

 angles a little prominent, rounded and concave behind with 

 an elevated line reaching to the origin of the wings ; scutel 

 colour of the thorax ; wings pale yellowish-brown, with 

 margined nervures ; poisers whitish ; feet somewhat paler 

 than the thorax; tergum polished; posterior segments 

 somewhat sericeous ; second, third, and fourth segments 

 with three abbreviated series of punctures near their bases. 



9 Length four-fifths of an inch. 



Of this interesting insect I obtained three specimens, 

 which were females. 



THEREVA, Latr. 



T. frontalis. Black; thorax with two yellow vittae : 

 tergum annulate with yellow. 



Inhabits North-west Territory. 



Head beneath with white hair; antennse., proboscis, and 

 palpi black ; front and vertex dusky yellowish, with a 

 large, deep black, glabrous, polished, transverse, undulated 

 spot ; thorax black with two yellow lines, or yellow with 

 three black lines ; wings hyaline, tinged with dull yellow- 

 ish ; nervures fuscous, slightly margined, and with a carpal 

 spot; scutel yellowish, with a dusky basal spot ; tergum 

 glabrous, polished, the posterior margins of the segments 

 bright yellow, wider upon the sides ; pleura and pectus 

 glaucous, the latter h^xry; poisers whitish, with a blackish 

 capitulum ; feet black; tibia excepting at tip dull testace- 

 ous ; venter cinereous, changeable, second and third seg- 

 ments with yellowish posterior margins. 



Length more than half an inch. 



