THE ENTOMOLOGIST. 83 



the Lepidoptera into Rhopalocera (butterflies, or day-flyers) 

 and Heterocera (moths, or night-flyers). It was no sooner 

 proposed by Boisduval tlian it was recognised as a most 

 convenient arrangement, and adopted very generally. The 

 antennaj in tliis order are always conspicuous, and their 

 clubbed or non-clubbed tips are easy of observation, and 

 associated with other important characteristics which sepa- 

 rate the two groups. The Sphingidae, however, by their 

 crepuscular habit, and their antennae thickening towards the 

 end, though terminating abruptly in a point, bring the two 

 groups in close relationship, and diminish their value ; while 

 the Castuiida), on the one hand, and the Hesperidaj, on the 

 other, so intimately connect them, that it becomes almost a 

 matter of opinion as to whether the former should be con- 

 sidered butterflies, or the latter moths. Urania and other 

 abnormal genera make the relationship of the two groups 

 still more perplexing. On anteuTial structure alone — whether 

 we consider the clubbed or non-clubbed tips according to 

 Boisduval, or the rigidity, direction, and length, which Mr. 

 Grote deems of greater importance — two primary divisions 

 cannot be based. If we lake the spring or spine on the hind 

 wings, which is so characteristic of the Heterocera, we meet 

 with the same difficulty, for a large number of moths do not 

 possess it, while an accepted Hesperian (Euschemon Rafflesiae, 

 MacL), from New South Wales, is furnished with it. Nor is 

 there any one set of characters which will serve as an infallible 

 guide to distinguish moths from butterflies; and the number 

 of moths described as butterflies, and the fact that Kirby 

 considers the position of Barbicornis, Threnodes, Pseudo- 

 pontia, Rhipheus, ^giale, and Euschemon, included in his 

 'Synonymic Catalogue of Diurnal Lepidoptera' as doubtful 

 butterflies, gives sufficient proof of the truth of the statement. 

 Between all classificalory divisions, from variety to kingdom, 

 the separating lines we draw get more and more broken in 

 proportion as our knowledge of forms, past and present, 

 increases. Every step in advance towards a true conception 

 of the relations of animals brings the diff'erent groups closer 

 together, until at last we perceive an almost continuous 

 chain. Even the older naturalists had an appreciation of 

 this fact. Linna^us's noted dictum, " Natura saltus non 

 facit," implies it; and Kirby and Spcnce justly observe that 

 " It appears to be the opinion of most modern jjhysiologists 



