vr BUTTERFLIES NYMPHALIDES 353 



is sure to be forthcoming and abundant before long, although 

 there may be little or none at the time the creature resumes 

 its activity. It is probable that the habit may be in some 

 way connected with an imperfect activity of the sexual organs. 

 It should, however, be recollected that many larvae of butterflies 

 hibernate as young larvae after hatching, and, sometimes, with- 

 out taking any food. Pyrameis cardui, the Painted Lady, is, 

 taking all into consideration, entitled to be considered the most 

 ubiquitous of the butterfly tribe. Its distribution is very wide, 

 and is probably still extending. The creature is found in 

 enormous numbers in some localities, especially in Northern and 

 Eastern Africa ; and when its numbers increase greatly, migration 

 takes place, and the Insect spreads even to localities where it 

 cannot maintain itself permanently. In Britain it is probably 

 during some years nearly or quite absent, but may suddenly 

 appear in large numbers as an immigrant. The favourite food 

 of the larva is thistles, but many other plants serve the Insect 

 at times. 



I'linessa, or Pyrameis, 1 atalanta, the Red Admiral, is common 

 in the Palaearctic and Nearctic regions, and extends its range to 

 various outlying spots. The most remarkable of these is the 

 remote Hawaiian Islands, where the Insect appears really to be 

 mw at home, though it is associated with a larger and more 

 powerful congener, P. tameamea. Another interesting Yauessid is 

 Araschnia levana, which is peculiar to Europe, where it produces 

 annually two generations so dissimilar to one another that they 

 passed current as two species, V. levana and V. prorsa. Although 

 intermediate forms are rare in nature they can be induced by 

 certain treatments applied to the larvae under human control. 



The dead-leaf butterflies of the genus Kallima belong to 

 Xymphalides. They are so shaped and coloured that when 

 settled, with wings closed, on a twig, the appearance is exactly 

 that of a dry leaf: the exposed surface is mottled with spots 

 that look just like the patches of minute fungi, etc, that are so 

 common on decaying vegetation. The colour and the spots on 

 the under surface of this butterfly are very variable. According 

 to Mr. Skertchly,' 2 we may presume that in the minute details of 



1 A most unfortunate diversity exists in the generic names applied to these 

 1'unessa, as well as in those of many other Lepidoptera. 

 -Ann. Xat. Hist. (6), iv. 1889, p. 212. 

 VOL. VI 2 A 



