12 Mr. H. Eltringliam's Monograjjh of the 



A. oncea shows a moderately good correspondence witli 

 the seasons in its various localities, the wet form of female 

 being black with a white subapical bar, whilst the dry- 

 season forms have the ground-colour reddish brown. 

 Examples from near Tete on the Zambesi, and from Ft. 

 Jameson correspond very nearly with the climatic con- 

 ditions, though on the other hand specimens from Chirni 

 Island, L. Bangweolo, taken in July, have wet-season males, 

 i. c. heavily spotted, and dry-season females, the latter 

 however, showing: but little indication of the fore-wiufj 

 white bar. The same condition occurs in May (dry) 

 specimens from Awemba, North-East Rhodesia. 



The foregoing examples seem to show that many 

 species do, in a general way exhibit a dimorphism which 

 may be termed seasonal, but before any profitable study 

 of this subject can be made, very much larger series of 

 examples must be available, labelled, not merely with the 

 precise locality, but also with the date of capture, and 

 further with what I think will prove to be of equal 

 importance, the elevation of the locality; and here I 

 may remark that though of late years, satisfactory label- 

 ling has received much greater attention than formerly, 

 and in one institution with which I am acquainted may 

 be said to have reached perfection, there seems still to 

 remain in the minds of some owners and keepers of 

 collections a very inadequate conception of the necessity 

 of full and correct labelling. 



Turning from seasonal to sexual dimorphism, we find 

 that this phenomenon is of very frequent occurrence in 

 the genus, in fact a marked difference in the appearance 

 of the sexes may be said to be the rule. Moreover, whilst 

 the females differ from the males one or both may be 

 polymorphic. Female polymorphism reaches its greatest 

 development in Acraea terpsickorc, of which it is possible 

 to arrange a long series in which no two individuals are 

 alike, and although the male of this species is also poly- 

 morphic, it presents nothing like the range of variation 

 exhibited by the female. In this case the different forms 

 seem to indicate merely a condition of extreme instability. 

 1 cannot associate anyone form of female with a particular 

 form of male, nor do any of the variations seem to be 

 governed by either seasonal or geographical conditions.* 



* In the $ the roiujcti form is certainly more characteristic of the 

 East and South, though the difference is not quite constant. 



