306 MOTIONS OF INSECTS. 



they seem to walk upon stilts ; but when we consider 

 that they have to walk over and amongst grass, the 

 former laying its eggs in meadows, we shall see the 

 reason of this conformation. Insects do not always 

 walk in a right line ; for I have often observed the little 

 midges (Psychoda, 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 zigzags. 



Numerous are the insects that run. Almost all the 

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

 beetles (Eutrecli\\\a\ and their fellow destroyers the Ci- 

 cindeltz, and other Eupter'ma which 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 

 tints 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 a . 

 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 

 (Hippobosca), and its kindred genus Ornithomyia pa- 

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

 have more than once experienced, from their extreme 

 agility. 1 lost one from this circumstance two years 

 ago that I found upon the sea-lark (Charadrius Hiati- 

 culd] and which appeared to be non-descript. Another 

 most singular insect, which though apterous is nearly 

 a Lesser, L. i. 248, note 24. 



