92 THE EXTERNAL ANATOMY 



thorax, and metathorax ; the upper side being respectively called 

 the pronotum, mesonotum, and metanotum, and the underside, 

 the prosternum, mesosternum, and metasternum. The pronotum 

 is the portion which in general language is called the thorax, and 

 in this species is large, rounded, and smooth, with a few punctures 

 near its sides ; its underside, the prosternum, which really consists 

 of three parts— the sternum, episterna,and the epimera— carries the 

 anterior pair of legs, which in this beetle are remarkably powerful. 

 In proof of the strength possessed by this beetle, I quote the 

 following : — 



" Having repeatedly placed one of these Dor-beetles, weighing 

 15 grains, under a weight equal to 4,796 grains, sufficient, it would 

 be considered, to crush its body, being 319 times its own weight ! 

 it heaved it up and withdrew, and the same pressure being placed 

 on its leg, it was immediately disengaged by the powers of the 

 other. A man to have accomplished a proportionate feat, must 

 have raised his body from an incumbent pressure of about 20 

 tons." — Knapfs Joimial of a Naturalist. From Science ■ Gossip, 

 1865, page 41. 



The legs, as in all insects, consist each of three important parts : 

 the femur or thigh, the tibia or shank, and the tarsus, which 

 corresponds to the hand or foot of man. The tarsi of this beetle 

 are small and weak, consisting of five joints, which is the normal 

 number ; the last joint being terminated by two moderately long, 

 curved, but very sharp claws. The tibise of the anterior legs are 

 very strong and wide, their outside edges having large teeth, 

 particularly towards their tips. These enable the beetle to loosen 

 the earth in front of it, so that with its other legs it is able to push 

 the material behind, and so work its way into the ground. They 

 are, in fact, its digging implements, acting much in the same way 

 as a gardener's fork, and everybody knows how much easier it is 

 to dig with a fork than it is with a spade. When the Beetle is 

 digging, the tarsi are folded back, and lie upon the tibia, and in 

 this way are preserved from injury ; the same plan may be noticed 

 carried out in all fossorial beetles. 



The femora are very large, as may be supposed, so as to 

 contain the very strong muscles necessary to move the legs with 

 the great power which the beetle has been shown to possess. It 



