514 MOTIONS OF INSECTS. 



course about on the surface of the sea between the tropics, and are remarka- 

 ble for beinf^ the only insects that have adopted tke sea for their abode^, 

 at least if we except the genera of beetles ^pns, Fogonus, Bhdius, 

 Hespcrophilus, fee, which burrow in the sand while covered with the 

 tide, and thus are partially inhabitants of the ocean. ^ One species of 

 Halobates (H. Streatficldana Templeton) was captured nearly midway 

 between the continent of Africa and America, by Colonel Streatfield, 87th 

 R. T. F., where numbers of them attended the Medusae."^ 



I am next to say a few words upon the motions of insects that burrow, 

 either to conceal themselves or their young. Though burrowing is not 

 always a locomotion, I shall consider it under this head, to preserve the 

 unity of the subject. Many enter the earth by means of fore-legs partic- 

 ularly formed for the purpose. The flat dentated anterior shanks, with 

 slender feet, that distinguish the chafers (Petahcera) — most of which in 

 their first states live under ground, and many occasionally in their last — 

 enable them to make their way either into the earth or out of it. Two other 

 genera of beetles (Scarites and Clivinia Latr.) have these shanks paj- 

 mated, or armed with longer teeth at their extremity, for the same purpose. 

 But the most remarkable burrower amongst perfect insects is that singular 

 animal the mole-cricket (Gryllotaljia vulgaris).^ This creature is endowed 

 with wonderful strength, particularly in its thorax and fore-legs. The 

 former is a very hard and solid shell or crust, covering like a shield the 

 trunk of the animal ; and the latter are remarkably fitted for burrowing, 

 both by their strength and construction. The shanks are very broad, and 

 terminate obliquely in four enormous sharp teeth, like so many fingers : 

 the foot consists of three joints — the two first being broad and tooth-shaped, 

 and pointing in an opposite direction to the teeth of the shank ; and the 

 last small, and armed at the extremity with two sharp claws. This foot 

 is placed inside the shank, so as to resemble a thumb, and perform the 

 office of one. The direction and motion of these hands, as in moles, is 

 outwards ; thus enabling the animal most effectually to remove the earth 

 when it burrows. By the help of these powerful instruments, it is aston- 

 ishing how instantaneously it buries itself. This creature works under 

 ground like a field-mouse, raising a ridge as it goes ; but it does not throw 

 up heaps like its name-sake the mole. They will in this manner under- 

 mine whole gardens ; and thus in wet and swampy situations, in which 

 they delight, they excavate their curious apartments, before described. 

 The field-cricket {Gryllus campcstris) is also a burrower, but by means of 

 different instruments ; for with its strong jaws, toothed like the claws of a 

 lobster, but sharper, in heaths and other dry situations it perforates and 

 rounds its curious and regular cells. The house-cricket (G. domestiais), 

 which, on account of the softness of the mortar, delights, in new-built 

 houses, with the same organs, to make herself a covered-way from room 

 to room, burrows and mines between the joints of the bricks and stones.^ 



But of all the burrowing tribes, none are so numerous as those of the 

 order Hymenoptcra. Wherever you see a bare bank, of a sunny expo- 

 sure, you usually find it full of the habitations of these insects; — and 



' Burmeister, Manual of Ent. 567. * Spence in Trans. Ent. Soc. Lond. i. 180. 



' Templeton in Trans. Ent. Soc. Lond. i. 230. 



* Plate II. Fig. 2. » White, Nat. HisL ii. 72. 76. 80. 



