1920] Holland, Lepidoptera of the Congo 219 



It happens that the present writer has before him a vevy large 

 series of specimens of the genus from various parts of Africa where it is 

 found. Over this mass of specimens he has long pored in the attempt to 

 liring order out of what seems chaos. Every one of the forms admitted 

 by Amivillius to have specific rank is to be found in this series, but 

 there are so many intergrading forms that it is impossible to decide 

 where one species begins and the other ends. Of course, by selecting 

 those which tally with the forms alread}" named and described and de- 

 stroying the rest, a semblance of specific security for these forms might 

 apparently be produced. But such a procedure would not be scientifi- 

 cally honest. In the first place, there is great variability in size among 

 specimens marked alike. Some are only 22 mm. in expanse, and they 

 range through various measurements up to 45 mm. in expanse. Some 

 have the outer margins of the secondaries heavily bordered with black; 

 in other specimens the hind margins are altogether free from black on 

 the margins; and there are intergrades between the two extremes. 

 Some are absolutely free from markings of any kind whatever on the 

 lower side of both primaries and secondaries; others are heavily marked, 

 as described and figured by authors; and there is every grade of 

 difference from those which are plain white on the under side to those 

 which are figured as is the insect named M. zymna by Smith and Kirby 

 and figured by them as such. Those with the light hind margins have 

 the same maculation on the under side as those which have the heavj' 

 hind margins. Nothing is absolutely fixed, and there is no key to the 

 puzzle, if regard be had to the maculation and markings of the wings. 

 The fact is, I am convinced, that we are dealing here with a species 

 characterized by great variability, both in size and markings. We have 

 over one hundred si:)ecimens collected at one locality in the Cameroons 

 during one summer. All of the so-called species are represented in the 

 lumch, and the writer, if he were disposed to do so, might describe several 

 others from the same catch, if he were willing to select some of the inter- 

 grading forms and dwell upon the presence or absence of this or that 

 spot, or the slight variations in shade which occur. Differences are 

 plainly and clearlj- distinguishable, but to the mind of the writer they 

 do not show specific diversity'. They rej^resent merelj^ individual 

 variation, and he is inclined to the belief that the whole congeries of 

 variant specimens are after all only referable to ilf. zymna (Westwood), a 

 protean species. There are vastly more females than males in the collec- 

 tion and, strangely enough, a multitude of the females are greatly 

 dwarfed, most of the specimens only measuring 22 mm. in expanse of 



