﻿170 EIGHTH ANNUAL REPORT 



"He v:ho, by a mbmtp analysis of any animal, enables us to solve any dubious point connected 

 therewith, does more for the elucidation of this much abusei naturalsyslem than the grealcit and most 

 injenious theorist who has yet taken the subject in hand." — Westwood. 



The study of aberrant forms in Nature is always interesting. Tliey are continually 

 •confronting the naturalist. Tiiey baffle the systematist and constantly remind him of 

 the necessarily arbitrary nature of his classificatory divisions. Few divisions seem 

 more natural at first glance, than that of the Lepidoptera into Rhopalocera (butterflies 

 or day-flyers) and Heterocera (moths or night-flyers). It was no sooner proposed by 

 Boisduval than it was recognized as a most convenient arrangement, and adopted very 

 generally. The antennre in this Order are always conspicuous, and their clubbed or 

 non-clubbed tips are easy of observation, and associated with other important charac- 

 teristics which separate the two groups. The Sphingid;^, however, by their crepuscu- 

 lar habit and their antenna? thickening toward the end, though terminating abruptly 

 in a point, bring the two groups in close relationship and diminish their value ; while 

 the Castnildoe on the one hand and the Hesperidte on the other so intimately connect 

 them, that i*", becomes almost a matter of opinion as to whether the former should be 

 considered butterflies, or the latter moths. Urania and other abnormal genera* make 

 the relationship of the two groups still more perplexing. On antennal 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 f — two 

 primary divisions cannot be based. If we take 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 {Euschemo7i 

 RafflesicB, 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 butter- 

 flies ; and the number of moths described as butterflies, and the fact that Kirby con- 

 siders the position of Barbicornis, Threnodes, Pseudopontia, Rhipheus, ^^giale, and Eus- 

 ■chemon. Included in his " Synonymic Catalogue of Diurnal Lepidoptera" as doubtful 

 butterflies, gives sufficient proof of the truth of the statement. Between all classifica- 

 tory 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 toward 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. Linnreus's noted dictum, 

 ''^ Natura salius non facit,^'' implies it; and Kirby and Spence justly observe that " it 

 appears to be the opinion of most modern physiologists that the series of affinities in 

 nature is a concatenation or continuous series; and that though an hiatus is here and 

 there observable, this has been caused either by the annihilation of some original group 

 or species * * * or that the objects required to fill it up are still in existence but 

 have not yet been discovered." Modern naturalists find in this more or less gradual 

 blending their strongest argument in favor of community of descent, and speculation 

 as to the origin, or outcome rather, in the near present or remote past, of existing 

 forms, is naturally and very generally indulged, even by those who a few years back 

 were more inclined to ridicule than accept Darwinian doctrine. Shall we then say that 

 the old divisions must be discarded because not absolute ? As well might we arffue for 

 the abolition of the four seasons because they differ with the latitude, or because they 

 gradually blend into each other ! Entomologists will always speak of moths and butter- 

 flies, howsoever arbitrary the groups may come to be looked upon, or however numer- 

 ous the intermediate gradations. 



* Westwood {Inlr. ii, 3.')9) figures Barbicornis Basalts, Gofl. as an Erj'cinid butterfly with tapering 

 and ciliate antenna;. 



t I'roc. Amer. Assoc. Adv. Sci. xxii, B. 111. 



