312 ANIMAL DEFENCES 



manner by palatable Butterflies belonging to several other families, 

 and also by certain Moths. Many of the mimicking species belong 

 to the Pieridae, which includes the common white Butterflies of 

 our fields and gardens, and these are naturally so unlike the 

 forms they mimic that Wallace remarks (in Darwinism): — "These 

 differences are as large and important as those between pigs and 

 sheep, or between swallows and sparrows; while English entomo- 

 logists will best understand the case by supposing that a species 

 of Pieris in this country was coloured and shaped like a small 

 tortoise-shell, while another species on the Continent was equally 

 like a Camberwell beauty — so like in both cases as to be mistaken 

 when on the wing, and the difference only to be detected by close 

 examination ". 



The Danaids are found in the warmer parts both of the Old 

 and New Worlds, though they are most abundant in the tropical 

 parts of Asia. Their various species are mimicked to a very 

 large extent, and one of these, the Black - veined Brown or 

 Monarch [Anosia erippus), is interesting as an American form 

 which has extended its range to this country. In its original 

 home it is imitated by a harmless Butterfly [Limeniiis misippns) 

 belonging to another family and closely allied to one of our 

 native forms, the White Admiral {Limenitis sibylla). 



It is evidently more important for the well-being of the race 

 that the female should be protected than the male, and it is a 

 fact that only the female Butterfly in some mimicking species 

 assumes the garb of an unpalatable species living in the same 

 area. The difference between the two sexes in such cases is so 

 great that they are liable to be mistaken for distinct species. 

 But this is quite a simple matter by comparison with a case 

 described in detail by Trimen, in which the females of a South 

 African Swallow-tail Butterfly {Papiiio merope) are of three 

 different sorts, unlike the male and unlike one another. The 

 reason for this is, that each of the three kinds mimics a distinct 

 species of Danais [D. echeria, D. niavi?ts, and D. ckiysippus). 

 Comparison with a closely-allied Swallow-tail {Papilio meriones) 

 from Madagascar gives us an idea of what the female of P. merope 

 was originally like. In this case there is no question of mimicry, 

 and the two sexes are very similar. 



Acrceids. — The members of the third Butterfly group notorious 

 for inedibility, i.e. the Acrseids, is found chiefly in tropical Africa, 



