Seasonal Dimorphism in African Butterflies 111 
my idea as to J. nachtiyali being a seasonal form of 
J. artavia when we received a collection from Nyasaland 
distinctly proving that both occurred together in splendid 
condition at the same season. I have also proved that 
J. simia, J. trimeni, and J. cuama fly there together 
throughout a considerable portion of the year, and cer- 
tainly both in the dry and wet seasons; this is somewhat 
disconcerting. 
In conclusion, I would observe that, whether the forms 
of Acrxa with black apex be proved by breeding to be a 
seasonal development of those which lack it, or not, there 
is not the slightest doubt that they are varietal forms, 
and not distinct species ; all of them, with the exception 
of A. caldarena, being already linked together by inter- 
grades in the British Museum series. 
9TH ApRriL, 1897. 
