1 Hj [May, 



ncrvure stand in a straight transverse line with the ending on 

 the cubitus, a little interior to its ending on the posterior 

 radius, which is the outermost. Penultimate (14th) joint in 

 the 3 antenna spheroidal, not beaked ; 15th rather smaller, 

 globular and apiculate or bulbose ; scape densely squamate ; 

 1st joint subovoid, subequal in length to the 2nd, which is 

 globular ; 3rd joint elongate, slightly stouter than the 4th 

 and apparently longer, although (by micrometer) of the same 

 length as it; 3rd-13th joints pastiniform, each furnished 

 with a pluriseriate outer verticil of hairs, and an inner verticil 

 of denser, long, fine, soft hairs, enclosing articular appendages 

 in the form of two opposite expanded, concave, ovate fascicles 

 of coherent soft hair, similar to minute membraneous striate 

 grass glumes 29. P. incerla. 



tt 13ristling hair on the radius confined entirely to the stem {prcBfurca). 



B.B.B. Bristling hair nowhere (unless on the postical nervure) extended 

 beyond the shortest line drawn from the end of the subcosta to 

 the end of the axillar ; its ending on the radius conterminous 

 with the stem, or very nearly so, and opposite or approximate to 

 its ending on the cubitus. Penultimate (14th) joint in the ^ 

 antenna obovoid or spheroidal, not beaked ; 15th apiculate ; 1st 

 joint short, obovoid ; 2nd subglobular ; 3rd ovoid or bulbose, with 

 a short stout beak, shorter than the 4th joint, and furnished with 

 a small verticil of hairs ; 4th-13th joints bulbose, with the beaks 

 long and filiform ; articular appendages long, slightly oblique, 

 curved subspirally half a turn. 



b^ Bristling hair wanting on the subcosta, radial branches, prsebrachial 

 ami anal nervures ; its endings from the radius to the postical 

 ncrvure disposed in an obtusely, angulate, transverse line 

 with one another, with the angle re-entering and at the an- 

 terior pobrachial nervure ; loth joint in the S antenna very 

 small; scape densely squamate Species ?fo. XV, Alg. 



b^^- Bi istling hair wanting on the subcosta, radial branches, prsebrachial, 

 anal, and probably on the posterior pobrachial ; its endings 

 from the radius to the axillar nervure disposed in an oblique 

 slightly zigzag line with one another, liaving obtuse salient 

 angles at the cubitus and postical nervure ; 15th joint in the 

 $ antenna bulbose, associated with the last pair of articular 

 appendages so as to appear amidst the surrounding hairs 

 figure of 8-shaped ; scape clothed with hairs and a few in- 

 conspicuous scales 30. P. revisenda. 



27. Pericoma ttsttjlata (Haliday, MS.), Walker. 

 P. ustulata, idem, Ins. Brit. Dipt., iii, 258 (1856) ; Etu., arite, 

 2nd ser., vol iv, 12S, and vol. v, pi. iii, P. 27— 27a (details). 



