STREPSIPTERA., 289 
94. 11. Xenos Rossii, after Jurine; 94.12. the same from nature.) 
The body is long and narrow, its greatest extent being occupied by 
a very large and singularly developed thorax. The general character 
of the body indicates great weakness, and we accordingly find that 
the insects live but a very short time in the imago state. The head 
and thorax are of a velvety texture. The head is distinct and ex- 
posed (jig. 93. 2. head of S. Spencii; 93. 3. ditto of S. Childrenii ; 
94. 2. under side of head, and front of body of Elenchus): it is trans- 
verse, with the eyes very large, lateral, and prominent, being placed 
upon the contracted sides of the head, which gives them the appear- 
ance of being inserted upon short foot-stalks. The number of hex- 
agonal facets is small, and they are singularly separated from each 
other by a septum or partition, which, being elevated above the 
lenses, gives the eyes a cellular surface. The lenses are much larger, 
and infinitely less numerous, especially in Xenos, than in other insects 
with compound eyes. (Kirby, /.c. p. 104.) In the last-named genus 
there are not more than fifty lenses. In Elenchus tenuicornis Mr. 
Templeton* could only detect about fifteen lenses in the eyes, which 
are quite sessile (fig. 94. 3. eye of Elenchus, from Mr. Templeton’s 
drawings). The front margin of the head is rather produced and 
deflexed below ( Trans. Ent. Soe. vol. i. pl. 17. f. 5.), but it does not 
appear to exhibit any transverse impression indicating the existence 
of a distinct clypeus, or upper lip; such, at least, is its character in 
the recent specimens which I have examined. Savigny, however, 
described this deflexed gradually narrowed part of the head, as a 
moveable labrum, in the “ characteres oris” which he communicated 
to Dr. Leach (Zool. Mise. vol. iii. p. 133).+ The composition of the 
mouth is very singular, exhibiting none of that complicated structure 
which we have seen in many of the preceding insects. This is, in 
effect, to be attributed to the fact, that the imago takes little, if any, 
food during its short existence.{ In the various specimens which I 
have examined and dissected, I have not, indeed, been able to detect 
* J am indebted to this gentleman not only for his unique specimen of Elenchus 
tenuicornis, together with specimens of his minute Mauritian Elenchus, but also 
for an elaborate MS. description and figures of the former species. 
t Jurine describes Xenos vesparum as having “ deux lévres, une supérieure, large, 
et cilige, et une inférieure beaucoup plus petite.” 
+ Speaking of the Xenos Peckii, Professor Peck states that it probably does not 
feed in the perfect state, like some Phalene, and only continues the species. (Linn, 
Trans. vol. xi. p. 92.) 
VOL. II. U 
