ACR/EINiE. 131 



they, in common witli the Danainw, owe tins immunity to their mal- 

 odorous and uneatable nature, which leads insectivorous animals to pass 

 them by,'^ Like the Danaince also, many of them are the objects of 

 " mimicry " by butterflies belonging to other groups — Nym2ohalinm, 

 Papilionince, and even a few LycKiiiiim — which do not possess the 

 advantage of unpalatableness. Two South-Afi'ican cases are noted in 

 the table given above, and ten or twelve others have been recorded 

 from Western Tropical Africa ; while one in Tropical South America 

 — that of Actinote Thalia — has been tabulated by Mr. H. W. Bates 

 {Trans. Linn. Soc. Zond., xxiii. p. 503). 



The spiny larvae of the Acrceince are very gregarious, feeding in 

 companies and fully exposed. They emit a rather offensive odour, 

 of the same character, but not so strong, as that of the perfect insects. 

 The various species known consume plants of several different orders, 

 and some (A. Horta, A. Acard) are very destructive to passion-flowers 

 in gardens. 



The sub-angulated elongate pupaa are remarkably handsome, and 

 usually very conspicuous from their white or yellowish ground-colour, 

 veined and streaked with black, and marked abdominally with orange 

 and black spots, orange tubercles, or pink filaments. Unlike the 

 immense majority of chrysalides, in which concealment is secured by 

 form and colouring, they seem to court observation ; and their showy 

 appearance, like that of the perfect insects, doubtless serves to indicate 

 to the hungry insectivore a distasteful morsel. 



Though ranging throughout the tropical regions, the Acrminm find 

 their main development in Africa and its islands, some ninety species, 

 or about two-thirds of the number known, being Ethiopian. From 

 South America thirty-eight are recorded ; while the Indian region pro- 

 duces but three, and the Australian only two species. Some highly- 

 interesting and peculiar forms of Acroja inhabit Madagascar. Planema 

 seems specially characteristic of West Africa, only two representatives 

 occurring south of the Tropic ; while of Acrwa twenty South- African 

 species are on record. 



Genus ACR^A. 



Acrsea,^ Fab., " lUiger's Mag., vi. p. 284 (1807);" Latreille, Enc. Meth., 

 ix. p. 10 (1819) ; Doubl. (Sections Hyalites, Gnesia, Telchinia, 

 Pareha), Gen. Diurn. Lep., i. p. 137-142 (1848). 



Imago. — Head rather broad ; palpi with the second joint long and 

 swollen, thinly clothed with hairs (which are much longer and bristly 

 beneath), and with the terminal joint minute. 



^ The peculiar odour of these butterflies seems to reside chiefly in a bright-yellow liquid 

 secretion, which, on pressure of the thorax, exudes somewhat coj^iously. 



The Acrceince are extremely tenacious of life, and their structure is so elastic that no 

 pressure of the thorax, short of absolute crushing of the tissues, sufEces to kill, or even 

 paralyse them. 



