LEPIDOPTERA 581 



like or feather-like ; only in rare cases are they enlarged towards tk" 

 tip. The moths have been termed the Heterocera* by many ento- 

 mological writers, in contradistinction to Rhopalocera,* a term ap- 

 plied to the butterflies. 



The butterflies. — All of our species of butterflies fly in the daytime; 

 and, with few exceptions, they fold the wings together above the 

 back in a vertical position when at rest. The antennse are thread-like, 

 and usually with a club at the tip. It was this feature that suggested 

 the term Rhopalocera, which is applied to them. 



The group butterflies as defined here includes the representatives 

 of two quite distinct superfamilies, the Hesperioidea or skippers, and 

 the Papilionoidea or true butterflies. The distinctive characters of 

 these two superfamilies are discussed later. 



The division of the Lepidoptera into moths and butterflies is an 

 artificial one, the group moths including representatives of both of 

 the two suborders into which the order is divided, as indicated above. 

 In the natural classification, the primary division of the order is 

 based on differences in the method of uniting the two wings of each 

 side, and on differences in the venation of the hind wings. In one 

 suborder, the Jugatse, the posterior lobe of the fore wing is specialized 

 so as to form an organ, a jugum or a fibula, which unites the fore and 

 hind wings; and the venation of the hind wings is similar to that of 

 the fore wings. In the other suborder, the Frenatae, the two wings 

 of each side are united by a frenulum in the more generalized forms 

 and by a substitute for a frenulum in certain specialized forms; and 

 the venation of the hind wings is quite different from that of the fore 

 wings. 



Hilbner's Tentamen. — At some undetermined date, but previous to 1810 and 

 probably in 1 806, Jacob Hiibner distributed a two-page work, giving a classifica- 

 tion of the Lepidoptera. This work is commonly known as " Hiibner 's Tenta- 

 men," tentamen being the first word in its long Latin title. Entomologists differ 

 regarding the standing of this work; some believe that it was merely privately 

 printed, while others regard it as a published work and adopt the generic names 

 that were used in it. This difference of opinion is the cause of serious confusion in 

 the names of certain genera and families. It seems to the writer that the evi- 

 dence supporting the view that the "Tentamen" was published is conclusive. 

 See "Entomologists Record and Journal of Variation," Vol. 31 (1919), Supple- 

 ment. 



SYNOPSIS OF THE LEPIDOPTERA 



The families comprising this order are grouped in various ways by different 

 writers ; none of these groupings can be regarded as final in the present state of our 

 knowledge. The following provisional arrangement has been adopted for use in 

 this book. 

 A. The Jugate Lepidoptera. — Moths in which the two wings of each side are 



united by a jugum or by a fibula, p. 592 Suborder Jugate 



B. The Microjugat^e. 



C. The Mandibulate Jugates. p. 592 Family Micropterygid^e 



CC. The Haustellate Jugates. p. 593 Family ERiocRANiiDiE 



BB. The Macrojugat^. 



The Swifts, p. 594 Family Hepialid^ 



*Heter6cera: hetero (^repos), other, different; ceras (/c^pas), a horn. 

 *Rhopal6cera: rhopalon {p6iTQ\ov), a club; ceras {Kipas), a horn. 



