COLEOPTERA. 



'57 



nearly always brightly metallic or otherwise conspicuous. Some of the species 



are very gregarious in their habits. Lina tremulce is often found in large numbers 



in all its stages on the leaves of aspen ; the larvae are 



somewhat like those of lady-birds, and have the habit 



of exuding a strong -smelling yellow liquid from the 



mouth and other parts of the body. The Colorado 



potato - beetle (Leptinotarsa decemlineata) is very 



destructive to the potato crops in North America. The 



Galerucince are poorly represented in Great Britain, 



while of the flea-beetles (Halticince) we have a large 



number of species, of which the best known are the 



turnip -flea (Phyllotreta nemorum), and other little 



jumping beetles which attack cruciferous plants. The 



larvae of the Halticince usually mine in the tissues of 



the leaf underneath the epidermis ; in this respect 



differing from the larvae of most of the other 



Ghrysomelidce. The Cryptostomata are distinguished 



by having the front of the head inclined backwards 



so that the mouth is almost completely hidden. Two 



subfamilies are included in this section. The Hispince 



are remarkable for the sharp projecting spines with 



which many of the species are armed, while the 



CassidincB have the characteristic form to which they 



owe their name of tortoise-beetles. In Great Britain, 



the tortoise-beetles are represented by half a dozen or more species of the genus 



Cassida, one of which (G. nebulosa) in its different stages is illustrated in our figure. 



COLORADO POTATO-BEETLE IN ALL 



ITS STAGES (nat. size). 



onn 



LIFE-HISTORY OF THE TORTOISE-BEETLES 



1, Cassida nebulosa ; 2, The beetle (enlarged) ; 3, The larva (nat. size) ; 4, The pupa, and 5, the larva (both 

 enlarged) ; 6, Desmonota variolosa, with leg and portion of elytron enlarged. 



A Brazilian species (Desmonota variolosa), remarkable for its deeply sculptured 

 elytra and bright golden-green colour, is also shown in the same figure. 



