410 Mr. Westwood's Illustrations of the 



The truly comparative nature of these relations has not been hitherto stated, 

 and hence, as it appears to me, has originated much of the misconception 

 which still exists even among professed naturalists, many of whom are 

 ready to admit the existence of relations amongst natural objects founded 

 upon more or less complete resemblances, but yet of equivalent value, without 

 perceiving the various natures, and consequently varied value, of such rela- 

 tions*. 



In the following pages I have first selected such species of insects as exhibit 

 an analogy with other species of the same order ; and secondly, such as illus- 

 trate the analogies between insects of different orders. 



That species belonging to two genera of the same family, or even subfamily, 

 may be analogous representatives of each other, is as clear as though they 

 belonged to different families or orders. Thus, although the genus Adelium, K. 

 is so excellent an example of analogy, when its species are compared with the 

 species composing the family Carabidce, that the specific names Caraboides, 

 Calosomoides, Licinoides, have been given to insects belonging to the former 

 genus, yet there may be relations of analogy existing among the species of 



* One of the chief difficulties connected with this subject is that of drawing the precise line between 

 these two kinds of relations (hence the difficulties connected with the true location of Mantispa) ; this 

 is not a little increased by the evident distinctions existing amongst each class of relations : thus affi- 

 nities may be so concealed as to escape the eye even of professed naturalists ; hence the Homopterous 

 genus Aleyrodes so completely puts on the appearance of a moth, that Linnseus named it Phalaena 

 Tinea proletella ; whilst Fabricius in all his works described an Orthopterous insect (Hymenotes rhombea, 

 Westw. Proc. Zool. Soc, 1837, p. 130.) under the Homopterous genus Membracis ; the precise relations 

 of these insects being disguised affinilies. The relation between the house- and field-cricket is an evident 

 affinity, but that which exists between the field-cricket and the mole-cricket is a disguised affinity, and 

 yet no one will question the propriety of these insects being considered as closely allied together, al- 

 though so totally different in form. Again, analogies may be equally disguised. No one, for example, 

 has ever supposed that one of the Carabidce and Paussus possessed any relation ; and yet not only do 

 Ozcma and Paussus crepitate, but both also possess a minute tubercle at the posterior external angle 

 of the elytra, which no other Coleopterous insects exhibit. In like manner, no one would suppose 

 that any relation could exist between a butterfly and a woodlouse (beyond that of each being a Con- 

 dylopodous animal), and yet by comparing the imperfect state of Thecla with the perfect state of Onis- 

 cus we find them to possess a disguised analogical relation. I mention these as instances of the many 

 trivial circumstances which may be collected as grounds for asserting the existence of analogical re- 

 lations, which are necessarily often of so diversified a character and so readily to be traced between 

 almost any given groups, as to lead to a supposition that they can afiford no decisive test of a natural 

 arrangement independent of more important considerations. 



