African Species of the Genus Acraed. 7 



Observations in the field show that the larvae of Acraea 

 are gregarious. The perfect insects are slow of flight and 

 indifferent to pursuit. Many emit an acrid juice when 

 injured, and all appear to be remarkably tenacious of life, 

 being not only protected by the extreme toughness of their 

 integuments from any mechanical injury, but also exhibiting 

 a great power of resistance to the effects of toxic substances. 

 Some small and apparently delicate species have been 

 observed to remain in full possession of their faculties after 

 more than half-an-hour's confinement in a cyanide bottle. 

 Such species as have been utilised for experiments in 

 palatibility provide evidence of a high degree of distaste- 

 fulness. Some of Marshall's experiments with a butterfly- 

 eating Mantis, suggest that when driven by the absence of 

 other food to an exclusively Acraeine diet, a diseased 

 condition, followed by death, ensued. In habits, some 

 Acraeas are fond of the open, whilst others are woodland 

 and forest species, and one or two are partial to marshy 

 districts. Trimen in his work on the South African Butter- 

 flies describes them as of a peculiarly quarrelsome disposi- 

 tion, fighting desperately for the possession of a particular 

 leaf on which to roost or to deposit their ova. From 

 Marshall's observations in his well-known paper on the 

 "Bionomics of South African Insects" the courtship of 

 Acraeas would appear to be carried out on the principle, as 

 he expresses it, of "marriage by capture," the male seizing 

 the female in the air. 



A very remarkable feature of the genus is the presence 

 on the female, in the majority of species, after pairing, 

 of a mass of hard wax-like material on the underside of 

 the abdomen. This secretion or seal * as it may be called, 

 occurs also in Planenia, Actinote, Amauris, Parnassiiis, Thais, 

 Uurycus, and Euryades. It seems to be composed of similar 

 material in all the genera mentioned, though in Acraea and 

 Actinote it frequently also contains a mass of hairs and 

 scales derived from the abdomen of the male, these being 

 often arranged in a beautifully symmetrical manner. What- 

 ever may be the purpose of this secretion in Parnassius and 

 in the other genera mentioned, its object in Acraea would 

 appear to be, as originally suggested by Professor Poulton,f 



* I submit the word sj^hragis as a technical term for this structure 

 (Gr. (T<ppay\s = a seal). The term has been kindly suggested to me 

 l)y Professor Poulton after consultation with Mr. Arthur Sidgwick. 



t See Trans. Ent. Soc, p. 539, 1902. 



