PTINELLA. 127 
TRICHOPTERYGINA. 
Body elongate; abdomen much longer than the elytra. 
Thorax more or less constricted; posterior coxe slightly 
laminated . Loe ee PrINELLA. 
Thorax not constricted ; posterior coxee simple. . . . . . CHAMPIONELLA. 
Body more or less oblong; abdomen not much longer than the 
elytra. 
Thorax constricted near the base. . . . - + + + «+ + PTERYCODES. 
Thorax not constricted. 
Thorax with the posterior angles more or less produced . TrichoPpTeryx. 
Thorax with the posterior angles not produced . . . . NepHanss. 
| PTILIINA. 
Base of the thorax incumbent on the shoulders of the elytra . . ActTIDIUM. 
Base of the thorax fitted to the shoulders of the elytra. 
Body very convex and shining, not pubescent. . - - - - PrenripiuM. 
Body more or less pubescent. 
Antenne very short. NANOSELLA. 
Antenne long. 
Thorax narrower than the elytra, with the hinder 
angles not produced . . . «ee + + + +) Priniv. 
Thorax as broad as the elytra, with the hinder angles 
THROSCIDIUM. 
produced . 
In describing the older genera of the Trichopterygide it will be unnecessary in the 
present work to enter into a detailed account of their anatomy, which, for the greater 
part, has been fully set forth in my ‘Trichopterygia Ilustrata.’ The characters which 
I purpose chiefly to notice are those which subsequent investigations and a more 
matured knowledge of the subject have, since the publication of that work, enabled 
me to add to or to correct in the descriptions there given. These, it will be seen, 
consist wholly in the respective proportions of certain parts of the underside of the 
external skeleton; a subject formerly much neglected, but of late years brought 
prominently forward, and placed in the important position which it now holds, chiefly 
through the investigations of Dr. Leconte and Dr. Horn. 
TRICHOPTERYGINA. 
PTINELLA. 
Ptinella, Motschulsky, Bull. Mosc. 1845, iv. p. 506 ; Matthews, Trich. Ilustr. p. 164, t. 19 (1872). 
in life translucent. Antenne 11-jointed, generally long and slender, ornamented with 
long hairs; club elongate, moniliform. Head prominent, rather large; eyes moderate, in some species 
deficient in the male sex. Thorax generally small, and more or less constricted near the base. Scutellum 
large, triangular. Hlytra abbreviated, often very short, separately rounded at their extremities. Abdomen 
Body elongate, slender, 
