INTRODUCTION. 85 



JEgocerides, &c. That of Crepuscular is adapted 

 more or less to some sphinges, but by no means to the 

 Zygenides, which fly only in the heat of the sun. 

 Finally, the term Nocturnal is not more properly 

 applicable to all the species, since many belonging 

 to this section appear only during the day. In order 

 to avoid these improper denominations, we have 

 substituted for the word Diurnal, that of Rhopalo- 

 ceres, proposed by M. Dumeril. Being unable to 

 perceive limits between the Crepuscular and Noc- 

 turnal divisions of Latreille, we have united those 

 two great sections under the name of Heteroceres. 

 In our method, therefore, the lepidoptera are di- 

 vided into two grand legions, JRhopaloceres and 

 Heteroceres*." 



Dr. Boisduval. then proceeds to explain that the 

 first of these divisions is characterised by antennas 

 thickening to a club at the extremity ; and the se- 

 condly having these organs variously shaped ; this 

 indeed is implied by the words themselves. The 

 first division is subdivided into three sections, ac- 

 cording to the manner in which the caterpillars 

 transform themselves into chrysalides. Such as un- 

 dergo this change by attaching themselves by the tail 

 and a band round the middle, form the first division, 

 named Succincti ; such as are suspended by the tail 

 only, the second, Penduli ; while those which form 

 a cocoon by rolling leaves together, compose the 

 third division, termed Involuti. 



* Species general des Lepidopteres, p. 158. 



