THE CANADIAN ENTOMOLOGIST. 203 



beautiful appearance when flying in the bright sunshine, and evidently 

 suggested the popular names given to them by the French and Germans. 



The Dragon-fly is usually found in the vicinity of small streams or 

 ponds, for reasons we will soon give. On bright and warm days in July 

 and August it may be seen skimming over the surface of the water or 

 ascending in graceful curves into the air, in search of food. When it 

 rests, its wings are expanded horizontally. 



Notwithstanding their graceful and " Demoiselle " appearance, they 

 are most bloodthirsty creatures. Their rapid flight and enormous range 

 of vision enable them to capture other insects with ease, while, their taste 

 not being limited, they can consume butterflies, moths and other insects 

 without compunction, and they are known to destroy and eat each other, 

 as well as very small fishes (Figuier). However, it is this ravenous 

 propensity which makes this insect so very valuable to man, as they 

 destroy immense numbers of other insects which are injurious to vegetable 

 and other products, and do not injure these substances themselves. A 

 few of them shut in a house will soon rid it of flies, bugs and mosquitoes, 

 and therefore their presence should be welcomed. The popular opinion 

 that they are dangerous to man is without foundation, as they can neither 

 bite, sting, or poison him. 



We may now consider the development of L. trimaculata from the 

 egg, as it furnishes some very curious and interesting information. 



When the female is about to deposit her eggs, she attaches herself to 

 some plant growing out of the water, and pushing her abdomen beneath 

 the surface, glues a bunch of eggs to the submerged stem or leaf (Uhler). 

 These eggs produce larvae which have a distant and ugly resemblance to 

 the perfect insect. The larva is active and passes its existence in the 

 water, feeding on numerous weaker insects. It possesses a curious syringe 

 like apparatus situated in the end of the body, by which it discharges a 

 stream of water for a distance of two or three inches behind it, thereby 

 propelling the insect forward. The motion thus given is most irregular 

 and appears to be beyond the control of the larva. This curious arrange- 

 ment serves for respiration as well as locomotion. 



The larva soon reaches the pupa state (corresponding to the chrysalis 

 state of a butterfly), in which it is also active, crawling over the bottom 

 of the stream preying on other insects. In this state it is longer than the 



