222 THE CANADIAN ENTOMOLOGIST. 



through the water with great ease. They may well be called the sharks 

 of the insect world, for there arc few tilings that live in the water which 

 are safe from their attacks. They are especial enemies of the larvae of 

 other aquatic insects ; they feed also upon tadpoles, molluscs and small 

 fish, and when pressed by hunger they do not hesitate to devour one 

 another. They may be kept in an aquarium and fed on water insects and 

 small pieces of raw meat, which they suck greedily. 



Fig. 13 represents this species very correctly ; it is black with a broad 

 margin of pale yellow on each side, and stripes of the same color across the 

 front of the head and on both the front and hind margins of the thorax ; 

 there is also an irregular yellow line crossing the wing covers near the 

 tip. The under side is somewhat paler with reddish markings. Examples 

 of this insect are often brought to us during the summer by persons who 

 have found them in tubs or barrels of water and who were puzzled to 

 know how they could get there. Beneath their hard wing covers they 

 have a large pair of membranous wings, by the use of which they can fly 

 with great ease ; by this means they are enabled to travel from pond to 

 pond in search of their prey. When wishing to change their location 

 they crawl out of the water (usually towards evening) either up some reed 

 or other water plant, or to the margin of the pond, and suddenly open 

 their wing covers, expand their wings and rise into the air almost perpen- 

 dicularly to a great height. Their descent is nearly as sudden and direct, 

 and they often, when descending, drop into the water with considerable 

 force. It would appear that they are enabled to distinguish the water 

 from a considerable height by its glassy surface, for sometimes they have 

 been known to drop with violence upon glazed garden sash, which they 

 had evidently mistaken for water. 



The female lays her eggs in the water, where they soon hatch into 

 voung larvae, possessing the ferocious disposition and voracious appetite 

 of their parents. The larvae grow rapidly, and when mature are about 

 two inches long, with large flattened heads armed with sickle-like jaws, 

 with which they seize other insects and hold them while they suck their 

 juices ; they sometimes quickly snip off the tails of young tadpoles, and 

 are known to attack young fishes and suck their blood. Many years ago, 

 when searching with a dip-net in a pond for the larvae of Dragon-flies, we 

 caught one of these savage creatures, and supposing it could be as safely 

 handled as the libellulaa larvae, took hold of it, when it quickly turned and 

 buried its sharp jaws in the flesh of one of our fingers, making the blood flow 



