278 MIMICRY AM) NATURAL SELFXTIOX 



Families iiiluibitini;^ tlic same region, a itndcncy which is 

 so pn^noimced in the case of the IlJio))iiinac and Hclico- 

 7iinac that lhe\ were Ion;/ rt'ijarded as a sinijle <'"roup. 

 although the structural dilterences between them, as larva, 

 pupa, and imago, are strongly marked and indicate that 

 the first Sub-ramil\- belonjjs to one side of the ^jreat 

 Nymphalid famih' and the second to the opposite side. 

 This remarkable unilormity in the species of certain 

 ])uttertl) Sub-bamilies was first exjjlained b) Professor 

 Meldola' on the lines suggested by Dr. Fritz Miiller''^ in 

 1879, viz. as an adaptation in order to reduce the amount 

 of life sacrificed during the period when young and inex- 

 i)erienced insect-eatiui/ animals are learniuLT to distinguish 

 between palatable and un[)alatable (and perhaps unwhole- 

 some) food. If two species living intermingled and 

 equall}- numerous are superficially exactl)- alike, and both 

 nauseous, each will lose only half the number of indivi- 

 duals which would have been required in order to educate 

 their enemies if they had been dissimilar. The sacrifice 

 of life is also reduced bv the stronor o-eneral resemblance 

 running through the sj)ecies of each specially protected 

 Sub-bamily in one country. Such resemblance is by no 

 means confined to the Rhopalocera (butterthes) or the 

 Lepidopt(Ta. It is found abundantly in all specially 

 defended insect Orders, principally the Ilymenoptera. 

 If we look at the Australian Aculeata we notice a lari^^e 

 group of species in which the orange ground colour is 

 deeper and browner than in banded Aculeata generally, 

 while the black zones are broader and fewer, being in fact 

 usuall) reduced to two, one crossing the thorax, another 

 the abdomen. This very characteristic ap[jearance is to 

 be found in Abispa^ liuDioics, Alas/or, Ody)i€7'jis^ Jytvibcx 

 and probably man)' other genera : it also occurs in mime tic 

 Diptera [Asi/idac), and Longicorn Coleoptera. Here is 

 a broad fact which receives an intelligible explanation by 

 Natural Selection, but by no other theory which has been 

 suggested. We can well understand, on the theory of 

 Natural Selection, why the members of specially defended 



Ann. Mag. Nal. Hist., Dec. 1882, p, 417. 

 Kosnios, May 1879, p. 100; also Kosmos, v, 1881. 



4 



