24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 5 1 



on a level with uppermost front edge of oral margin, or above or below same. 



i) Peristomalia (lateralia of Robineau-Desvoidy ; peristomal ridges, the 

 ridges on lower edges of peristoma or checks, extending to vibrissa) with one 

 or many rows of bristles, extending hi w far up; parallel above oral margin, 

 divergent, convergent; parallel, divergent, convergent posteriorly below oral 

 margin ; effect on epistoma. 



2) Peristomal bristles (those on peristomalia) strung, weak, in one or 

 more rows, or few and with row of hairs. 



1) Epistoma (epistoma of Rob.-Desv.; Mundrand of Br. and v. Berg.; the 

 portion of facial plate below vibrissal angles and enclosed between the peristo- 

 malia, its point of junction with the mesofacial plate being indicated by the 

 vibrissal angles) projecting nose-like, prominent in profile, retreating, set 

 back or removed, produced downward or anteriorly, turned up, drawn out 

 tube-like, transversely cut off, broad, narrow, thin ; thickened, widened on 

 edge, callous or indurated, projecting forward and downward below vibrissas ; 

 drawn up in middle to form anterior part of narrow oral slit, its sides thereby 

 becoming nearly parallel; square, or curved in front outline. [The characters 

 of the epistoma are usually best included in those of facial plate, of which it 

 forms a part.] 



Oral margin (the anterior edge of the oral cavity, being the lower edge of 

 epistoma) . 



1) Oral cavity covered over transversely in front with an oblique pos- 

 teriorly-extending skin or membrane developed probably from the clypeus, 

 open, elongate, short, wide, narrow, deep, shallow, slit-like, or closed. 



1) Clypeus (clypeus of Rob.-Desv., Lowne, and Berlese; the anterior or 

 dorsal plate of the cephalopharvngeal skeleton, or fulcrum, of the rostrum) 

 distinct, rectangular, triangular, developed into a plate closing oral cavity, or 

 vestigial. 



1) Mouth parts normal, vestigial, immovably fixed at base of shallow oral 

 cavity, hidden in a narrow deep oral slit, or wanting. 



2) Proboscis short, fleshy; not longer than head height, shorter or longer 

 than same ; very elongate, bristle-like, twice geniculate, once geniculate, slender 

 and horny, large, stout, vestigial, or absent. 



2) Labella well developed, large, broad, small, vestigial. 



2) Palpi absent, vestigial, filiform, club-shaped, strongly elongate, normal. 



1) Longitudinal axis of head at oral margin longer than that at insertion 

 of antennae, or the two equal, or the former shorter. 



1) Facial profile advancing thereby, or more or less straight or concave, 

 or receding or convex. 



1) Facio-peristomal profile angular, rounded, strongly or gently convex. 



1) Antennae (arising from antennal ridge of Lowne; from antennale or 2d 

 somite of front of Berlese) inserted above, on. or below a line drawn through 

 middle of eyes ; above or below middle of extreme head height, widely sepa- 

 rated or closely approximated. 



1) Second antennal joint strongly elongate compared with first, longer 

 than shortened third joint, normal, with or without strong bristles on front 

 edge. 



2) Third antennal joint entire, fissiform in one or both sexes, elongate, 

 narrowed, widened, enlarged, with curved point on front apical corner, normal. 



1)2) Arista bare, microscopically pubescent, hairy, pectinate, partly or 

 wholly plumose, geniculate, flattened, thickened in what part of its length; first 



