COLEOPTEROUS INSECTS. 133 



and it is somewhat shining. It is liable to great 

 variation in size, some of the specimens which we 

 have seen, among an extensive series in the posses- 

 sion of James Wilson, Esq. measuring three and a 

 fourth inches in length, and an inch and a half across 

 the elytra, while others do not exceed two inches 

 in length and one in breadth. It is a native of 

 Java, and seems to occur in considerable plenty in 

 some parts of the country. 



DYTISCID^E. 



A numerous group of carnivorous beetles, belong- 

 ing to the present section, inhabit the waters of 

 lakes and ponds, both as larvae and in their perfect 

 condition. Although frequenting an element so 

 different in its nature from that in which other in- 

 sects live, there is no very marked difference in 

 their structure, a slight modification of certain parts 

 sufficing to adapt them to their new abodes. Their 

 motions are effected by means of the hinder pair of 

 legs, which are rather long and flat, and have the 

 tibiae and tarsi densely fringed with long stiff hairs, 

 presenting a pretty broad surface to the water. 

 Their respiratory apparatus in no respect differs 

 from that of other insects ;. but, in order to bring the 

 stigmatic openings in contact with the air, they are 

 obliged from time to time to repair to the surface. 

 This is speedily effected merely by stopping the 

 movements of the legs ; for as the body is specifically 



