368 MODERN CLASSIFICATION OF INSECTS. 
February, 1831.). M. de Johet attributes it to the action of the 
air being suddenly impelled against the scales at the base of the 
wings by the action of the latter (as cited by Engramelle). Such is 
also the opinion of Vallot (in Z’Lnstitut, 1834, p. 4.), whilst M. Lorey 
attributes it to the escape of a current of air through certain cavities 
at the base of the abdomen, which are furnished with a beautiful 
pencil of hairs. M. Goreau has also described this apparatus as the 
cause of the sound. (Ann. Soc. Ent. France, 1837. p. 69.) 
It is to be observed, however, that this opinion, supported as it is 
by analogy with the Cicadz, appears to be negatived by the fact, 
that many mute Lepidoptera are furnished with these cavities and 
pencils of hairs. (See my figures of Noctuide.) 
This gigantic insect has the habit of frequenting the hive for the 
purpose of robbing the bees of their honey, as described by Kuhn, 
Huber, and others; these authors conjecturing that the hostility of 
the bees is disarmed by the noise emitted by the moth. This moth, 
when it bursts from the chrysalis, has its wings, antenne, and legs 
enveloped in a fine membrane resembling tissue paper, which pre- 
vents them from adhering, and rapidly dries, opens, and drops off as 
they unfold. This pellicle I regard as the analogue of the Pseudi- 
mago skin of Ephemera (see anté, p. 28. note). Goeze (Der 
Naturforscher, st. 17.) has published a singular variety of the larvee of 
Ach. Atropos. Fuessly also figured some varieties in the larve of 
Deilephila Livornica (Arch. tab. 4. 33. Sph. Koechlini), supposed 
to be caused by the diversity of the food of the larva. 
.The species of Smerinthus appear to be subject in a remarkable 
degree to gynandromorphism, a considerable number of instances 
of this kind having been recorded by different authors, which I have 
collected in a memoir read before the Entomological Society, in 
which I have also described and figured some very interesting indi- 
viduals reared by Mr. House, being hybrids between S. ocellatus and 
S. populi, which are the only instances hitherto recorded of a similar 
result produced by a forced union of the sexes of distinct species. I 
am indebted to W. Raddon, Esq. for one of these very interesting 
specimens. Deilephila Euphorbiz is stated to remain in the pupa 
state occasionally for two years, a wise provision of nature, result- 
ing from the habit of this insect in frequenting the sand hills near 
the coast, which, constantly shifting with the changes of the seasons, 
might destroy the entire brood were it not for such a protection. 
