168 lUJLLKTlN 4.-., INITEl) STATKS NATIONAL MUSEUM. 



Mfsouotiuu without furrows: lattTal ocelli <los«' to tin- iuarj;iii of the eye. 

 Autuima* tilifortu, iiioiiiliforiii, or .siiliiiioiiiliforiii. 

 Basal uerviire distinct; niandililes liifid. 



Head nineh broader than the thorax; eyes bare; anteiuue taperinjj toward 

 apex; basal abdoiuiiial segiueut as wide as the iiietathorax. 



Acorus Fiirster. 



Head snhqnadrate, but slightly broader than the thorax; antenna^ slightly 



thickened toward apex; basal abdominal segment petioliform, mmh 



narrower than the metathorax Bakis Haliday. 



Basal nerviire wanting; mandibles tridentate. 



Head transverse, scarcely broader than the thorax; eyes liairy; antenna- 

 slightly thickened at tip; basal abdominal segment transverse, not 

 quite as wide as the apex of metathorax Ac»>u>ii>ES Howard. 



THORON Halidty. 



Eut. Mag., I, p. 271 (183:^); Fiirst. Hym. Stud., ii. p. 100 (1856). 



{Tyi>e T. fornicatun Nees. = T. nutallicnH Hal.) 



Head rather large, transverse, the oceiput and cheeks margined; 

 ocelli 3, triangularly arranged, and wider apart than in Prosacantha; 

 eyes large, oval. 



Anteunjp inserted close to theclypens, 12-jointed in both sexes; in 9 

 clavate, the club solid, although shoeing traces of sutures; in $ long, 

 filiform, the pedicel small, oval, the flagellar joints nearly equal, about 

 4 times as long as thick, pubescent. 



Maxillary palpi 4-jointed; labial palpi 2-jointed. 



Mandibles tridentate. 



Thorax ovoid, the prothorax visible from above as an arcuate line, 

 depressed anteriorly; mesonotum with li impressed lines; metathorax 

 very ;ihort, rounded at the sides. 



Front wings with the submarginal vein joining the costa behind the 

 middle; the marginal vein very sliort, thickened; i)Ostmarginal vein 

 not, or scarcely, developed ; the stigma' vein longer than marginal, thick- 

 ened at base, and terminating in a little knob. 



Abdomen oval or oblong-oval, strongly narrowed at base, the flrst 

 segment longer than wide, the third the longest. 



Legs long, slender, pilose, the femora clavate, the; tibiie subclavate, 

 with spurs 1, 1, 1; the tarsi ^ery long and slender. 



Thoroii pallipes Aslim. 



(PI. XVI, Fig. H, 9.) 



Ent. Am..in,p. 99. 



9. Length, 2""". Black, polished; hejid subquadrate, smooth, the 

 face convex; mandibles bluntly 3-dentate at ti]»s, pale rufous. Meso- 

 notum sparsely punctate, with 2 farrows posteriorly; metathorax and 

 pleura rugose. Antennae 12'jointed, dark brown, the scape and pedi- 

 cel brownish-yellow. Leg^s, including coxte, pale or yellowish. Abdo- 

 men oblong-oval, a little longer than the head and thorax together, 

 attached high up on the metathorax, the first segment i)etioliform, 



