MOTIONS OF INSECTS. 283 



Hy it produces Tipuin amphibia : it seems not clear, 

 from his figure, to which of the modern genera of the 

 TipuUdcB it belongs. 



I come now to the jumping apodes, and one of this 

 description will immediately occur to your recollec- 

 tion," — that I mean which revels in our richest cheeses, 

 and produces a little black shining fly (Tephritis jmtrisy 

 F.). These maggots have long been celebrated for their 

 saltatorious powers. They effect their tremendous leaps 

 — laugh not at the term, for they are truly so when 

 compared with what human force and agility can ac- 

 complish — in nearly the same manner as salmon are 

 stated to do when they wish to pass over a cataract, 

 by taking their tail in their mouth, and letting it go 

 suddenly. When it prepares to leap, our larva first 

 erects itself upon its anus, and then, bending itself into 

 a circle by bringing its head to its tail, it pushes forth 

 its unguiform mandibles, and fixes them in two cavi- 

 ties in its anal tubercles. All being thus prepared, it 

 next contracts its body into an oblong, so that the two 

 halves are parallel to each other. This done, it lets 

 go its hold with so violent a jerk that the sound pro- 

 duced by its mandibles may be readily heard, and the 

 leap takes place. Swammerdam saw one, whose length 

 did not exceed the fourth part of an incli, jump in this 

 manner out of a box six inches deep ; which is as if a 

 man six feet high should raise himself in tiie 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 rather diflerent. These 



* Swamm. Bibl. Nat. Ed. Hill. ii. 64. b. 



