14 CLASS INSECTA. 



which the author gives in the article Insects of the ." Dic- 

 tionnaire Classique d'Histoire Naturelle." Before adopting 



(the three forming the breast,) and one upper which forms the back ; the 

 lower one takes the name of sternum. The lateral part or side, is divided 

 into three principal pieces : one which attaches to the sternum, and is 

 called episteitiuniy another placed behind this last, and to which the 

 haunch is articulated, is named ephneros. A small moveable piece, which 

 serves for the union of the latter with the haunch, hitherto unknown, is 

 named trochantin, from its opposition to the trochanter ; the third piece 

 of the side, which is the mesothorax and metathorax, placed in front of 

 the episternum and under the wing, is called hypopteron ; sometimes there 

 is, moreover, around the stigma a small corneous piece, named per'itreme. 

 The upper part of each segment, which the author names tergum, is di- 

 vided into four pieces, named according to their position in each ring — 

 prcescutum, scutum, scutellum, and post-scutellum. The first is often, and 

 the fourth almost always, concealed in the interior. Naturalists have 

 generally distinguished only the scutellum of the metothorax, which is 

 often remarkable for its size and configuration, but its analogue may be 

 found in the three segments ; thus the trunk of insects may be divided 

 into twenty three principal pieces, and if the hypoptera be reckoned, the 

 number of these pieces may extend to forty-three, more or less visible in 

 the interior. One portion of these pieces, moreover, gives out, internally, 

 divers productions which also merit names, in consequence of their im- 

 portance and uses. Thus from the lower part of the sternum of each 

 segment arises within a vertical apophysis, sometimes figured like a y, and 

 which M, Audouin names entothorax. It furnishes attachments to the 

 muscles, and protects the medullary cord. Its analogue is found in the 

 head, and sometimes in the first rings of the abdomen. Other internal 

 prominences result from the elongation of the neighbouring external 

 pieces, united by a sort of synoptosis. M. Audouin names them apodc- 

 viata. Some give an attachment to the muscle, others to the wings. 

 Finally, there are some more small moveable pieces, either internally 

 between the muscles, or at the base of the wings, which the author names 

 epidemata. We have said that the principal pieces, or their vestiges, are 

 always found, but it by no means follows, that they are always separate ; 

 many among them are even always united in certain genera and certain 

 orders, and are only distinguished by the traces of sutures " — — M. Audouin 

 has since changed, in his article of Insects, in the " Dictionnaire Classique 



