LETTERS ON ENTOMOLOGY. 157 
whose history I shall give you. It belongs to 
a genus between the dragon-fly and the heme- 
robius ; its length is about half an inch, and in 
shape it resembles a woodlouse, though more 
triangular : it has six legs, and the mouth is 
armed with curved jaws like horns. It lives 
upon the juices of other insects, chiefly ants ; but 
as it always walks backwards and very slowly, 
you may perhaps wonder how it gets any food, 
particularly as it will not touch any animal it has 
not previously killed, and then only sucks the 
juices; but you will no longer wonder when 
you hear of its admirable stratagem. It digs a 
conical pit in loose sand, at the bottom of which 
it lies concealed to seize upon the unwary insects 
that, going too near the brink, fall down the 
sides. It first finds a soil of loose dry sand, near 
which it is indeed generally placed by its mother, 
and near some old wall or tree ; it next traces a 
circle in the sand, and proceeds to hollow it, by 
Ending on the inside of the circle, thrusting 
the hind part of its body under the sand, and 
using its fore-leg like a shovel to load its flat 
square head, with which it jerks the sand out- 
side to the distance of some inches. Walking 
backwards, and constantly repeating this process, 
it soon ^ goes round the circle, when it proceeds 
4' 
