136 THE YOUNG NATURALIST. [JuNE 1889 . 



line and structure, that nearly all resemblance is lost. These scales 

 exist in immense numbers on both upper and underside of the wing, 

 and are usually readily detachable, the merest touch sufficing to 

 remove them in quantity as a fine, slippery dust. 



The wings of lepidoptera are sometimes split or divided, as in the 

 Pterophori, or plume moths, but these rays or feathers all branch from 

 the same root. The females of some species are apterous, without 

 wings, others possess these appendages in a rudimentary form, and. 

 as such, unfit for flight, while one species, Lobophora hexaptera is the 

 fortunate possessor of six, four true wings, and two smaller ones or 

 winglets. 



The hind- wings of butterflies and plume moths are not folded, but 

 perfectly flat and rigid, while those of the moths are folded longitudi- 

 nally — that is to say, from the base to hinder-margin, and concealed 

 by the upper-wings during repose. 



Many species can easily be distinguished while on the wing, by 

 their peculiar and characteristic flight. In the Hymenoptera and 

 Aphides, we noticed that the wings are held together by a series of 

 hooks, and a similar arrangement is found to exist in the lepidoptera, 

 never, as far as I can discover, among the butterflies, but frequently 

 among the moths. 



The costal margin (see Fig. 9, representing the underside oiAcherontia 

 atropos) at a short distance from the insertion of the wing, is furnished 

 with a large and well developed loop, apparently formed by an exten- 

 sion of the walls of the nervure. This is covered with hairs or scales, 

 and sometimes seems to consist of incurved hairs alone. Attached to 

 the root of the under wing on the same side is a strong curved bristle, 

 longitudinally striated, passing through the loop on the upper wing, 



and locking the two members to- 

 gether, we chiefly find them in swift- 

 flying moths, but only in a complete 

 form in the males, though the opposite 

 sex not unfrequently have the num- 

 ber of bristles multiplied, but possess 

 no loop on the upper wing. They 

 are very apparent in the males of the 

 Sphingidae — A. atropos, S. ligustri, 

 F 'g- 9 - euphorbia and galii, C. elpenor, M. stella- 



tarum and others being well provided, the other sex lacking both hook 

 and bristle. A curious exception seems to occur in 5. ocellatus, for in 

 neither sex could I discover the slightest trace of either. 



