THE LEPIDOPTERA. 73 



merits of cabbages, carrots, or oak leaves as their future nourish- 

 ment, for, at the most, she dips her long sucker into a few 

 flowers to enjoy their sweetness. Nevertheless she deposits her 

 eggs in a safe place, and as near as possible to the ordinary 

 nourishment of the future caterpillar. 



It is impossible to explain the varieties of the colouring of 

 some groups of the Lepidoptera, or the remarkable resemblances 

 which exist between the tints of others. Sometimes all the 

 species of a genus have the same shades of colour and markings. 

 The most brilliantly tinted kinds belong to the hottest and 

 moistest climates ; for instance, South America, the Moluccas, 

 and certain parts of India. 



Several groups of species belonging to the great genus Papilio 

 have a very uniform system of decoration. Species of this genus, 

 which are found in the Moluccas, in the neighbourhood of the 

 Straits of Sunda, in India, and in Southern China, have black 

 velvety wings, dusted with a metallic blue or green tint, and 

 ornamented with spots or bands of the same shade. Other 

 species of the genus belonging to South America, to the Antilles, 

 and to Mexico, are distinguished on account of a flaring red 

 spot, or a band with opalescent tints, which ornament the black 

 hinder wings. Multitudes of others have their wings variegated 

 with yellow and black colours. 



The Pieridi, whose type is the great Cabbage Butterfly, have 

 usually white wings, and the species of the genus Colias have 

 them tinted yellow ; moreover, most of those of the genus 

 Morphos, of South America, have their wings brilliantly coloured 

 with a metallic blue. 



Thus there is a sort of uniformity in the ornamentation and 

 colouring of more or less widely spread natural groups of the 

 Lcpidoptera. But if we seek the reason why, and endeavour 

 to discover the end that Nature had in view in giving certain 

 shades of colour to certain species, we shall not obtain very 

 satisfactory answers. It is known that the brilliant colouring 

 depends upon the presence of the scales, so far as the Lcpidoptera 

 are concerned, and the microscope has proved that no inherent 

 and tangible colouring matters exist in those tiny dust-like 

 particles. The delicate ridges and net-work of the scales act 



