NATURAL HISTORY. 35 
remains stationary for a short time longer, while 
the wings expand and unfold themselves; the 
remaining parts are then liberated, and when 
sufficiently extended and dry, the perfect fly 
soars into the atmosphere. 
This fly has four reticulated wings, and is 
equally predaceous with its larva, feeding on 
butterflies and other insects. They may be 
taken, in June and July, on plants and on the 
banks of ponds:—they are vulgarly called horse- 
stingers, though entirely destitute of a sting. 
The French give them the name of Demoiselles ; 
surely our neighbours are too gallant to name 
them thus from the very amiable habits they 
exhibit in wantonly destroying every inoffensive 
insect they meet. In courtesy we must suppose 
it is from the elegance of their form, and the 
brilliant colours which adorn them. 
For microscopic observation this larva pos- 
sesses much interest, in exhibiting, in a very 
distinct manner, diffused circulation. This is 
well shewn in the legs, especially the joints 
next the body. The mask, eyes, rudimentary 
wings, and the leaflet tails, afford permanent 
objects when mounted in Canada balsam. 
