82 THE ENTOMOLOGIST. 



classification will be supported by every fact that we can observe, 

 whether it be a fact of habit or of structure, of the larva, or of 

 the imago. 



Every fact that tends to group species together may be proof 

 of relationship, probably is, but it may be an instance of what is 

 familiar to all as convergence. Every f-act that separates two 

 species unquestionably separates them. Whether specifically, 

 generically, or more profoundly, will usually depend on its 

 agreement or otherwise with other similar facts, as much as on 

 its own apparent importance. In any case of two groups being so 

 separated the presumption is strong that the relationships 

 within each group are closer than of any members of one group 

 to any of the others. 



The great and very frequent exception to this is where two 

 or more groups split up by a differentiation common to all of 

 them, usually in some character that is liable to great variation 

 under frequently occurring changes of environment. As an ex- 

 treme case, admitting no doubt, I might illustrate by saying that 

 many species of Lepidoptera have pale and melanic races. No 

 one would suggest that the pale races all belong to one family or 

 genus, and all the melanic ones to another. Or, we might say 

 that all species having apterous females belong to one family. 

 This is not so absurd an illustration as one might suppose, since 

 I fancy there are still to be found entomologists who think Psyche 

 and Orgyia are very closely related, practically on this ground 

 only. 



It is but recently that the Arctiad nature of the Syntomids 

 has been fully acknowledged, and their resemblance to Anthro- 

 cerids (Zygsenids) admitted to be convergent only. Whilst the 

 likeness that obtains between the Nolidae and Lithosiadae appears 

 strong enough to deceive the very elect. 



The objections that are raised to consideration of the earlier 

 stages in classification include two that I may allude to. The 

 first is usually expressed in something of this form — Is not the 

 imago the more complete and evolved form, and ought we not 

 therefore to classify by it, and not by the larva or pupa ? This 

 proposition is open to two serious comments. The first takes 

 note that the objector considers that classification is to be founded 

 on one stage only, probably on one character, or at most on a 

 very few characters, and, having so made his classification, 

 anything that contradicts it in any way is necessarily wrong. 

 The second comment is — he assumes that the upholder of the 

 use of the earlier stages in classification possesses precisely the 

 same narrow views, and is going to classify, say, by some larval 

 character, and flout everything that does not agree with his 

 results. The only excuse he has is, of course, that a certain 

 element of this nature must always exist. Life is short and art 

 is long, but science is longer still, and so we must all specialize, 



