122 THK KNTOJIOI.lXilSl's KKCOllD. 



Be it noted that these two genera are not founded on one (or any) 

 genitalic characters, nor did I found them. They (as at present 

 understood) were founded by Tutt without any reference to genitalic 

 characters. These characters, however, coming in support of an 

 already adopted position, are of vastly greater force, than if they were 

 the original and only basis for these genera. 



Mr. Bethune-Baker a^ain asks me how I should separate these 

 genei'a apart from the aedoeivjus. So far as the imagines go, I answer 

 at present, " I don't know." I should expect there is some character, 

 but for its discovery I fear we must wait until we have another Tutt, 

 with more time than Tutt had, to devote to this question. 



As regards my negative answer, it is largely founded on the dis- 

 covery of Agyiades alexins as a species distinct from PohjoiiuiiatKs iearns, 

 these have been accepted by everybody, Tutt says for more than the 

 last 50 years, as merely varieties of one species. As there are still 

 amongst English Entomologists not a few who are sceptical as to the 

 value of the male appendages for systematic purposes, it may be well 

 again to reiterate what I believe to be a correct estimate of their use 

 for this purpose. 



Broadly, they are on all fours with any other characters. Definite 

 and constant differences in two forms imply the two forms are distinct 

 species. The exception to this is where the diftjprences are not great, 

 and where the two forms seem to be geographical varieties. They are 

 in fact incipient species. In such cases, of course, where the two forms 

 are neither two "good " species, nor yet one homogeneous species, the 

 appendages no more than other characters will say they are either one 

 or the other. It is possible for two forms that are unquestionablj'^ 

 distinct to have very similar appendages, but as a matter of fact I 

 cannot call to mind any instance where this is certainly the case. 



It is to be remembered that the appendages are not one simple 

 organ, but are two whole segments (out of fourteen), and important 

 segments at that, of the insect, with their appurtenances ; they are of 

 very definite and distinct hard chitinous structure, enabling their con- 

 formation to be ascertained with certainty. In not a few cases there 

 can be little doubt that they are a chief item in species being or 

 remaining distinct from each other. No very long separation of a 

 species into two segregated groups is perhaps necessary, for these parts 

 (which are not bound in natural selection by the general environment, 

 as most other characters are), for one group to drift away from the 

 other in their morphology ; a small group perhaps very rapidly ; as it 

 is only constrained so far that all individuals within the group shall 

 vary together. 



The conclusion I arrive at is that if it be desirable and convenient 

 to separate these two genera, adequate characters on which to define 

 them are not wanting ; if on the other hand it be neither desirable or 

 convenient to do so, it is no more necessary to do so, than it was for 

 Linnaeus to place machaon and brassicae in different genera. I myself 

 regard it as desirable for convenience of study to keep them separate. 



Whitsuntide in the Midlands. 



By RUSSELL E. JAMES. 

 The date of Whitsun this year falling during the first few days of 

 June, my son and I made arrangements to run down to one of the 

 favourite haunts of Carterocep/ialiis j)alaejiion in Northamptonshire. 



