LEPIDOPTERA. 191 
The S. tiliz, much more common however on the Elm, the S. 
demi-paon, S. populi, S. querci, &c., compose this subgenus. They 
are heavy Insects, and the inferior wings project beyond the superior, 
as in several of the genus Bombyx(1). 
Our third division, that of the Srs1apEes, comprises those in which 
the antenne are always simple, fusiform and elongated, and fre- 
quently terminated as in the preceding subgenera, by a little bundle 
of setz or scales; in which the inferior palpi, slender and narrow, 
have three very distinct joints, the last tapering to a points; and 
where the extremity of the posterior tibiz is armed with very stout 
spines. The abdomen in most of them is terminated by a sort of 
brush. 
The caterpillars feed on the internal part of the stems or roots of 
plants, like those of the Hepiali and Cossi, are naked, without a pos- 
terior horn, and construct their cocoons in these stems with the 
debris of the substance on which they have fed. 
SEsIA. 
Where the antenne are terminated by a little tuft of scales. The 
wings are horizontal and marked with transparent spots. Thescales 
of the posterior extremity of the abdomen form a brush. Several of 
these Insects bear a close resemblance to Wasps or other Hymenop- 
tera, to Diptera, &c.(2) 
Tuyris, Hoff. Illig. 
The Thyrides resemble the Sesiz, but their antennz are much 
more slender, almost setaceous, and destitute of the terminal tuft. 
Their wings are angular and dentated. Their abdomen terminates 
in a point. 
M. Bois-Duval, whose knowledge of Lepidoptera in general, and 
of those in Europe particularly, is not inferior to that of our most 
celebrated entomologists, and who is about to publish a Monograph 
of the Zygznides that has received the approbation of the Royal 
Academy of Sciences, has observed the metamorphosis of the most 
known species(3). 
(1) See Encyc. Méthod., article Smerinthe; and Godart, op. cit. 
(2) See the Monographs of the Sesia by Laspeyres, Hiibner, Godart, &c. 
(3) Sphinaz fenestrina, Fab.; Lat., Ibid. 
