Manchester Memoirs, Vol. xliii. (1899), No. 3. 33 



the mandibles, the front broad, depressed ; the eyes mar- 

 gined behind. Antennae of medium length, not much longer 

 than the abdomen ; the third joint slightly longer than 

 the fourth. Scutellum raised ; its centre stoutly longitu- 

 dinally keeled throughout. Blotch indistinct, patella 

 distinct ; the claws bifid. Wings as in Tenthredo ; the 

 humeral nervure in the hind wings received beyond the 

 transverse discoidal. 



Differs from Tenthredo in the eyes converging beneath 

 and in not reaching to the base of the mandibles. The 

 antennae are longer than in Rhogogastera, and with the 

 third joint shorter compared with the fourth. The prin- 

 cipal feature, however, of the genus lies in the very strongly 

 keeled scutellum, a structure which does not occur in any 

 known species of the Tenthredinides. The pleurae are 

 straight, not rounded on the lower side, the edge at its 

 junction with the sternum being distinctly margined ; the 

 orbits behind have a sharp keel above but not on the 

 extreme outer edge. The parapsidal furrows are not very 

 distinctly defined. The fore calcaria are rather peculiar, 

 they are straight above ; the apex much narrowed and 

 sharp ; before it is a large, acute, straight projection, much 

 larger than usual. 



RETHRA CARINATA, sp. nov. 



Nigra; capite thoraceque punctatis, ore pedibusque 

 flavis, genicidis, tibiis tarsisque posticis nigris ; alis fulvo- 

 hyalinis, nervis stigmateque nigris. ?. 



Long. 1 1 mm. 



Antennae black ; the scape sparsely pilose ; the flag- 

 ellum almost glabrous. Front and vertex punctured, the 

 vertex finely and closely, the front coarsely, especially in 

 the middle, but the sides of the front at the apex are 

 smooth and shining ; the front depressed in the middle, 



