NEMATUS AECTICUS. 181 



88. NEMATUS AROTIOUS. 

 PI. XXV, fig. 6, Saw. 



Nematus arcticus, Thorns., Hym. Scand., i, 134, 62. 



Black, the head and mesonotum finely punctured, semi-opaque, 

 covered with close, short pale pile, the underside of the antenna), head, 

 except the part immediately surrounding the ocelli, pronotum, tegulse, 

 upperside of the pleurae and legs, reddish-yellow ; the anus and belly 

 dark testaceous, sternum and pleurae shining ; the coxae at the extreme 

 base and a spot at the base of femora are black. Antennae thin, nearly 

 as long as the body, the third and fourth joints being almost equal ; 

 clypeus deeply incised, apex of mandibles brownish. The wings are 

 ample, hyaline, strongly iridescent, costa and stigma yellowish-testa- 

 ceous ; the second recurrent nervure is received considerably in front 

 of the transverse cubital one ; the third cellule is a little more than half 

 the length of the second, and is very slightly dilated at the apex ; the 

 third transverse cubital nervure slopes a little towards the lower outer 

 edge of the wing. 



Length 2J lines. 



The above is the description of one of the two 

 British specimens I have seen of this species. The 

 other has the mesonotmn yellowish with three black 

 marks, the black part of the pleurae with two pale 

 splashes, the anal segment of the abdomen above, the 

 sides and belly entirely yellowish-red. In both the 

 sheath of saw is black, projecting and pilose at the 

 apex. 



The only British species with which arcticus can 

 be confounded is N. rumicis, from which it differs 

 in having the antennae longer and thinner and not 

 entirely black, the wings likewise wanting the yel- 

 lowish tinge, while the incision in the clypeus is deeper, 

 the sutures on vertex less distinct, spurs somewhat 

 longer and cerci shorter. 



Not common. One specimen taken by Mr. Joseph 

 Chappell in the Manchester district, and another by 

 the Eev. T. A. Marshall, also in England. The only 

 other locality known is Sweden. 



