THE BEETLES 3093 



larvae seem to live an exceptionally long time. There is at the present time in the 

 Natural History Museum in London a block of wood containing a living longicorn 

 larva, which for the past five or six years has been feeding and burrowing in the 

 wood. The larva was brought to the museum in a boottree, which its owner 

 previously had in constant use for over fourteen years. Other cases are on record 

 in which beetles have been seen to emerge from furniture in houses, after having 

 apparently passed an even more prolonged larval existence. 



Beetles, whether from the extent of their numbers or the variety of their 

 shapes and instincts, are well qualified to play an important part in the economy of 

 nature. Their chief function is that of universal scavengers. Not only do they 

 dispose of the smaller quantities of dead and decaying animal and vegetable matter 

 passed over by larger animals, but, by their own peculiar methods, they are enabled 

 to attack and clear away even the carcasses of quadrupeds of large size, and the dead 

 trunks of the largest trees. Owing to the compactness of their shape, and the 

 solidity of their outer covering, they are adapted for a much greater diversity in 

 modes of life than is possible for insects of other orders. Besides groups fitted to 

 act as scavengers, we find further series of forms that live in, and prey upon, all 

 kinds of plant life. There are groups again, either of terrestrial, arboreal, or aquatic 

 habits, which seek for, and prey upon living animales of the smaller kinds. Some 

 beetles live within the depths of the darkest caverns; and in such cases, having 

 no use for eyes, they are generally blind. Others are to be found dwelling as 

 "guests" in the homes of the ants and termites. Although the beetles cannot 

 boast of such a long line of ancestry as the cockroaches and other Orthoptera, yet 

 their records go back to an early period in geological history. There is no certain 

 evidence that they existed in Paleozoic times, and their first appearance has not 

 been traced farther back than the beginning of the Secondary epoch. The earliest 

 undoubted fossil remains of Coleoptera occur in the Swiss Trias, and from this 

 period onwards fossil beetles are to be met with in greater or less abundance in 

 rocks of different ages. They are especially well preserved in amber; and from 

 the Tertiary amber beds on the Baltic thousands of specimens have been collected. 



Of the beetles now existing, quite one hundred and thirty thousand different 

 species have been described, and, considering the rate at which new species are be- 

 ing yearly added, it is probable that before the end of the century the number of 

 named species will fall little short of one hundred and fifty thousand. 



SECTION PENTAMERA 



Beetles in which all the tarsi are five jointed. In this section there comes first 

 a great tribe of beetles, which, on account of their carnivorous tastes and predaceous 

 habits, are known as the Adephaga. Their whole organization seems well adapted 

 to enable them to capture and devour their prey, and it is in the modifications di- 

 rected to this end that some of the chief distinguishing characteristics of the tribe 

 are to be found. Their legs are fitted for speedy locomotion, and their jaws for the 

 cutting and tearing operations to which they are usually applied. The mandibles 

 are acutely pointed and have sharp cutting edges; and the inner lobes of the max- 



