284 MOTIONS OF INSECTS. 
‘raise himself in the air by jumping 144 feet! He had 
seen others leap a great deal higher?. The grub of a 
little gnat lately noticed (Tipula stercoraria, De Geer) 
has a similar faculty, though executed in a manner ra- 
ther different. These larvee, which inhabit horse-dung, 
though deprived of feet, cannot move by annular con- 
traction and dilatation; but are able, by various serpen- 
tine contortions, aided by their mandibles, to move in 
the substance which constitutes their food. Should any 
accident remove them from it, Providence has enabled 
them to recover their natural station by the power I am 
speaking of. When about to leap, they do not, like the 
cheese-fly, erect themselves so as to form an angle with 
the plane of position ; but lying horizontally, they bring 
the anus near the head, regulating the distance by the 
length of the leap they mean to take; when fixing it 
firmly, and then suddenly resuming a rectilinear posi- 
tion, they are carried through the air sometimes to the 
distance of two or three inches. They appear to have 
the power of flattening their anal extremity, and even of 
- rendering it concave: by means of which it may proba- 
bly act as a sucker, and so be more firmly fixable >.— 
The grub of a fly whose proceedings in that state I have 
before noticed * (Leptis Vermileo, F.), will, when remoy- 
ed from its habitation, endeavour to recover it by leap- 
ing. Indeed this mode of motion seems often to be given 
to this description of larvee by Providence, to enable 
them to return to their natural station, when by any ac- 
cident they have wandered away from it. 
Many apodous larvee inhabit the water, and therefore 
4 Swami. Bibl. Nat. Ed. Hill, ii. 64. b. & De Geer, vi. 389— 
© Vou. 1. 4th Ed. 432. 
