( xfviii ) 



Tlie various kinds of siuiilaritics sliortly rclV'rred to are met witii attain in 

 other groups of insects. Tliey demonstrate, we think, not only that there are 

 various ways to arrive at and different causes for resembhiuce, but also that 

 there is abundant material of similarity in details upon which selection may 

 seize, and modify and augment the incipient resemblance, and i)roduce those 

 wonderful likenesses whicli illustrate that fascinating iihenouienon called 



Mimicry. 



A studv of resemblance from this ]K)int of view is incidentally also a study 

 of relationship, and therefore an essential part of classification. It is well known 

 that the older students of Entomology were fret^uently taken in by similari- 

 ties which do not indicate rehitionship, associating often widely different species 

 on account of superficial resemblance. The older systematic works, and old 

 collections which have not been disturbed, testify to this abundantly. Bnt even 

 modern work, or rather work of recent date, is not free from striking blunders 

 of this kind, although the flourishing study of Mimicry has, or should have, 

 made everybody suspicious of mere resemblani^es in aspect. We well remember 

 trying in vain to convince a famous Lepidopterist, now dead, that the streaked 

 Indian Papilio mararci/s, .rrnocles, etc., are not nearly related to the streaked 

 form of Papilio clytia ; and we notice in a recent number of Lepidoptera Indica 

 that the mimetic Papilio rhett'iiof and its models are housed in the same 

 Moorean genus. The association of the Sphingidae with the Aegeriidae and 

 Zi/gaenidae from Linne down to recent times was due to a certain similarity in 

 the shape of the antennae being erroneously interpreted as meaning relationship. 

 The older writers were the more convinced of the correctness of the association 

 of the Aegeriidae with the Hawk Moths, since the clear-winged Aegeriids 

 ai)peared to them to be connected with the ordinary Sphingidae by the equally 

 clear- winged species of the Sphingid genera Cephonodes and Haemorrkagia. 

 The fallacy of the conclusion has now become evident to every student of 

 Lepidoptera, though perhaps not to every collector of " flies." The similarity 

 of Pseudonphinx tetrio to species of Protoparce, the " Bombycine "' appearance of 

 Arctonotus lucidus and Lapara, the resemblance of Deidamia inscriptum and 

 other Philampelinae to certain AmbuUcinae (= Smerintkinae auct.), the agree- 

 ment in appearance between Proserpinus Jiavofasciata and Haemorrkagia, of 

 Ni/cenjx In/potsticta and Amplgpterus, of Akbesia davidi and Proserpinus, of 

 Sesia and Leucostrophus, etc., etc., have freijuently misled even modern classifiers 

 of Sphingidae. 



The student who tries to build uj) a classification based on relationship has 

 to beware esi)ecialiy of two kinds of similarities referred to above : (1) similarity 

 as the outcome of reduction, and (2) similarity as the result of adaptation to 

 similar extraneous objects or to each other. 



The first point is the more frequently overlooked in classification, and re(^uires 

 some further explanation. 



If a, b, c, d are four organs of a s]:ccies or a genus, and «', b', c', d' the 

 same in their most reduced state ; if, further, the species or genus develops 



