310 iMOTIONS or INSECTS. 



amongst grass, — the former laying its eggs in nicadowii, 

 — we shall see the reason of this conformation. In- 

 sects do not always walk in a right line ; for I have 

 often observed the little midges {Psi/choda^ Latr.), 

 when walking up glass, moving alternately from right 

 to left and from left to right, as humble-bees fly, so as 

 to describe small zig-zags. 



Numerous are the insects that run. Almost all the 

 predaceous tribes, the black dors, clocks, or ground- 

 beetles (Carnbiche), and their fellow destroyers the Ci- 

 cindelidce, — which last Linne, with much propriety, has 

 denominated the tigers of the insect world, — are gifted 

 with uncommon powers of motion, and run with great 

 rapidity. The velocity, in this respect, of ants is also 

 very great. — Mr. Delisle observed a fly — so minute as 

 to be almost invisible — which ran nearly three inches 

 in a demi-second, and in that space made 540 steps. 

 Consequently it could take a thousand steps during one 

 pulsation of the blood of a man in health^. Which is 

 as if a man, whose steps measured two feet, should run 

 at the incredible rate of more than twenty miles in a 

 minute ! How astonishing then are the powers with 

 which these little beings are gifted ! — The forest-fly 

 {Hippohosca)^ and its kindred genus Ornithomyia pa- 

 rasitic upon birds, are extremely diflicult to take, as I 

 have more than once experienced, from their extreme 

 agility. I lost one from this circumstance two years 

 ago that I found upon the sea-lark {Charadr'ms HialU 

 cula, L.), and which appeared to be non-descript. 

 Another most singular insect, which though apterous 

 is nearly related to these — I mean the louse of the bat 



^ Lebscr, L. i. 248, note 24. 



