MOTIONS OF INSECTS. 479 © 
divers. Of this kind are the aquatic bugs (Gerris lacustris, Hydrometra 
stagnorum, Velia rivulorum, &c. Latr.). The first can walk, run, or even 
leap, which it does upon its prey, as well as swim upon the surface. The 
second, remarkable for its extreme slenderness, and for its prominent hemi- 
spherical eyes—which, though they are really in the head, appear to be in 
the middle of the body— rambles about in chase of other insects, in con- 
siderable numbers, in most stagnant waters. The Velia is to be met 
with chiefly in running streams and rivers, coursing very rapidly over their 
waves.’ The two last species neither jump norswim, The species of one 
genus of this group (Ha/obates Eschscholtz) course about on the surface 
of the sea between the tropics, and are remarkable for being the only in- 
sects that have adopted the sea for their abode*, at least if we except the 
enera of beetles Zpus, Pogonus, Bledius, Hesperophilus, &c., which burrow 
in the sand while coyered with the tide, and thus are partially inbabitants 
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 
Medusze.* 
Tam 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 preservé the 
unity of the subject. Many enter the earth by means of fore-legs particu- 
larly formed for the purpose. . The flat dentated anterior shanks, with 
slender feet, that distinguish the chafers ( Petalocera) — 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 Clivina Latr.) have these shanks 
palmated, 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 (Gryllotalpa vulgaris). This crea- 
ture 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 astonishing 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 namesake the mole. They will 
in this manner undermine whole gardens; and thus in wet and swampy 
situations, in which they delight, they excavate their curious apartments, 
before described. The field-cricket (Gryllus campestris) is also a burrower, 
but by means of different instruments; for with its strong jaws, toothed 
! Curtis, Brit. Fnt. t. ii. 2 Burmeister, Manual of Ent. 567 
5 Spence in Trans. Ent. Soc. Lond, i. 180. 
* Templeton in Zrans. nt. Soc, Lond, i. 230, 
