LEPIDOPTERA NOCTURNA. 87 



wanting: antennas simple, occasionally pectinated, but mostly ciliated in the 

 males, rarely serrated: head not very small: thorax stout, very frequently 

 crested: bodi/ moderately stout, the apex of the males tufted: winirs subtri- 

 gonate, generally deflexed, rarely convoluted, sometimes horizontal or in- 

 cumbent, undivided. Larva generally with sixteen feet, rarely fourteen, the 

 anal ones never deficient : pupa generally subterranean. 



The almost insurmountable difficulties that present themselves, 

 at nearly every step, in our endeavours to detect the characters of 

 Lepidopterous insects, are in no place more evident than amongst 

 the insects of this subdivision, owing to their great similitude, 

 and the obscurity of their characters; the trophi, which are such 

 important organs in other orders, being more or less enveloped 

 in scales or hair. We must therefore select our characters from 

 external differences of outline, colour, and texture; as also from 

 the structure of the antennae, the disposition of the wings, &c. 

 during repose, and as far as practicable from the metamorphoses 

 and economy : but, with all these aids, the insects approximate so 

 closely, that, notwithstanding the diversified materials of which the 

 Nocturna are manifestly composed, it is utterly impossible to frame 

 characters for the various genera, that shall include every species 

 truly belonging to each respectively, and exclude such as do not. 



If the metamorphosis be taken as a primary guide in the sub- 

 division of the Lepidoptera into families, we must doubtless con- 

 sider the indigenous Nocturna as composed of several; the first of 

 which has a larva attenuated at each end, and more or less hairy, 

 with sixteen legs : the second a cylindrical larva, generally naked, 

 but sometimes thickly clothed with hair, and always having sixteen 

 legs ; the third of such insects as have a naked larva with fourteen 

 legs ; and a fourth of such as have a larva with sixteen legs, but the 

 two anterior abdominal ones evidently shortest, the body naked, 

 ciliated laterally, and frequently having two prominences on the 

 anal segment ; though, as the perfect insects resemble each other so 

 greatly, and their characters are manifestly not only excessively 

 obscure, but have not been examined with sufficient accuracy to 

 the requisite extent, I shall merely subdivide the present group into 

 the two following families, which appear to be sufficiently distinct. 



r valde elongatae ; Sffipi:ssime convolute : pa/nj cylindrici : . 1. Lithosxid^e. 

 Ala; ■( 



I vix elongatae ; haud convolutas : ^ff/^i subcompressi : . 2. NoctuidjE. 



