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ill his mind's eye the species which bear on their under surface the numerous eye-like 

 spots distinctive of our " common blues," and he gives a figure of P. Corydon ; yet most 

 modern classifiers, neglecting these indications, place the polyommatous or "many- 

 eyed" species in the genus Lycsena, and apply the name Polyommatus to species 

 which have no eye-like spots at all. In the case of a genus which is originally 

 established on a single species, the negative evidence afforded by the non-indication of 

 other species as belonging to the genus, is almost tantamount to an express indication 

 of typicality. 



But (to come now to Mr. Kirby's paper), when the founder entirely omits to give 

 any indication, is the first in his list of species necessarily to be taken as the type- 

 species ? is ihe first section of the genus necessarily the typical section? j\lr. Kirby's 

 proposed reform is based entirely on this proposition, which he terms an " axiom." 

 But instead of being axiomatic, either self-evident, or an established proposition, 

 I think it is capable of distinct disproof; and that so far as Linne, Fabricius, and the 

 older authors are concerned, it can be shown to demonstration that in many cases, 

 whilst they have not indicated what ivas their type, they have indicated that their first 

 species, or first section, was not. In the first place, an insect that is once the type of a 

 genus must ever remain the type; yet (as mentioned by Mr. Pascoe) Fabricius, in the 

 successive editions of his works placed different species at the head of the same genus, 

 and (if my memory serves) Linne did the same. Again, the species of which dis- 

 sections, &c., are given is frequently not the first species in the genus. And (what 

 seems to my mind decisive on the point) look at Linne's description of Cimex: "«/« 

 qualuor, cruciato-complicatae: superioribus anterius coriaceis:" the first section of 

 Cimex is "apieri," and at the head of the genus is the wingless C. lectularius. The 

 notion of a wingless insect being the type of a four-winged group is somewhat 

 amusing ! I believe other instances, not quite so startling, but in principle the same, 

 might be adduced in abundance; but Cimex, if it stood alone, is enough to show that, 

 so far as Linne is concerned, the notion of taking the first species, or first section, as 

 the type, is simply the reverse of what the author intended. It may be that the Cimex 

 of Linne (as was argued by Mr. Butler respecting Papilio) is not properly a genus at 

 all; but whatever it be, it must I think be clear that in the contemplation of Linne 

 himself, the first section or species of Cimex was not his type of Cimex. 



In a detached paper, containing descriptions of genera taken haphazard and at 

 random, there may be some presumption in favour of the notion that the species first 

 described is typical of the genus; and even in a complete systematic work, there may 

 be a slight presumption in favour of the typicality of the first species of a genus 

 which (like Papilio) is placed (as it were) at the top of the tree. But as regards any 

 other genus than the first in the list, it seems to me that in a systematic work or 

 catalogue the presumption would rather be against the first species; for suppose three 

 genera, A, B and C; the arrangement being necessarily linear, and following the 

 affinities of the species, the first species of genus B would be that which most nearly 

 approached genus A, just as the last species of genus B would be that which most 

 nearly approached genus C ; and it would be neither at the top, nor at the bottom, but 

 about the middle, of genus B, that we should find the species of B which was most 

 different from both A and C, which species would presumably be the ideal representa- 

 tive of genus B, would presumably have that aggregate of characters which constitute 

 the genus B, and distinguish it from A on the one hand and from C on the other. 



