336 INSECTA. 



and by the extract published by the author in the article INSECTES of 

 the Diet. Class. d'Histoire Naturelle. Before we can adopt his 

 nomenclature, and apply it generally, we must wait until his work 

 and the figures which accompany it are published ; for all practical 

 purposes, however, the denominations already introduced may suffice. 

 A second production relative to the same subject, which both justice 

 and friendship here compel me to notice, is that of M. Chabrier on 

 the flight of insects. It forms part of the Mem. du Mus. d'Hist. 

 Nat., but is sold separately. The figures are executed on a great 

 scale, as are also those of a Memoir of Jurine, Sen. on the wings of 

 the Hymenoptera, a work, like the preceding one, which is the result of 

 infinite patience. 



As Insects inhabit all kinds of dwellings, they are provided with 

 all sorts of locomotive organs, wings and feet, which in several, act 

 as fins. 



The wings are membranous, dry, elastic organs, usually diapha- 

 nous, and attached to the sides of the back of the thorax : the first, 

 when there are four, or when they are unique, on those of its second 

 segment, and the second on those of the following or of the meta- 

 thorax. They are composed of two membranes laid one on the other, 

 and are traversed in various directions by more or less numerous 

 nervures, which are so many tracheal tubes, now forming a network, 

 and then simple veins. A celebrated naturalist, Jurine, Sen., has 

 taken advantage of the disposition and decussation of these nervures * 

 in a systematic point of view. The Libellulae, Apes, Vespae, 

 Papiliones, &c., have four wings ; but those of the latter are covered 

 with small scales, which at the first glance resemble dust, and give 

 them the magnificent colours in which they are drest. They are 

 easily removed with the finger, and that portion of the wing becomes 

 transparent. By the aid of glasses we discover that these scales are 

 of various figures, and implanted in the wing by means of a pedicle, 

 arranged gradually and in series, like tiles on a roof. Before the 

 superior wings of these Insects are two species of epaulettes ptery- 

 goda which extend posteriorly along a portion of the back on which 

 they are laid. The wings of some Insects remain straight, or are 



unites it with the thorax, and thus also we find that the two medullary cords form 

 two contiguous ganglions under the mouth. In accordance with these views, we 

 consider the first segment of the body of the Scolopendrae, that which bears the 

 two hooks, as an analogous division of the head. It seems that Knoch had distin- 

 guished the epimera by the names of scapula and parapleuree, the post-pectus by 

 that of acetabulum, while the mediopectus was his peristathium. The first joint of 

 the four posterior coxae, in most of the Coleoptera, forms a transverse plate, enclosed 

 in the flanks, and is the piece, as far as I can judge, that he calls the moerium. 

 * See general observations on the Hymenoptera. 



