18 Mr. H. Eltringham's Monograph of the 



theories of species formation. The information that, on 

 the one hand, zetes and chile had been definitely proved to be 

 the same species, or, on the other, that loelwitschii welwitschii 

 and ivelwitschii alboradiata were certainly specifically 

 distinct, would, though interesting, not alter the existing 

 fact of their close relationship. 



It only remains to give certain explanations of some 

 remaining features of the work. The appended chart of 

 the wing neuration is merely a diagram to illustrate the 

 numbers and terms used in the descriptions. The draw- 

 ings of genitalia have been made from the actual prepara- 

 tions by means of a Leitz reflector, and are intended to 

 illustrate the characteristic form in each case, though it 

 must be borne in mind that such conclusions as have been 

 based on these structures, have not been arrived at from 

 the drawings, but from the preparations themselves, ex- 

 amined from various points of view. In a very few cases, 

 paucity of material has precluded the preparation of more 

 than one specimen. In the majority of species, series of 

 preparations have been made, not only from different 

 individuals, but also, where possible, from different locali- 

 ties. Only by so doing, can a correct estimate be made of 

 the range of individual variation, which, though small in 

 Acraea, does occur, and is not to be confused with specific 

 difference. It may be objected that the figures are not 

 all drawn from the same point of view. The view adopted 

 however, is that, which in each case, seems best to show 

 the characteristic structure. 



In addition to the figures of male genitalia I have made 

 a small number of drawings of the chitinous plates which, 

 in the female, surround the external opening of the bursa 

 copulatrix. These structures, though very characteristic 

 of some species, are in others but slightly developed. 

 Unfortunately the latter condition persists in many 

 species of which the male armature furnishes little guide 

 to specific distinction. I have also illustrated a few ex- 

 amples of the peculiar structure of the sphragis or copu- 

 latory seal, though this feature, even when well developed 

 is not, I think, of much systematic importance. 



For the opportunity of illustrating the larvae on Plate 

 VI, I am entirely indebted to my friend Mr. W. A. Lamborn, 

 who, with praiseworthy care, has preserved and forwarded 

 the specimens together with notes as to colour, correspond- 

 ing to a colour chart Avith which I provided him. The 

 illustrations of imagines have been drawn in every case 



