22 AQUATIC INSECTS. 



emerge in early summer, and then one may observe millions of the 

 cast nymphal skins clinging to the stones along the hanks of 

 streams. A gaping slit along the upper side of the thorax shows 

 how the adult emerged. The adults are poor fliers and are easily 

 caught. Mating takes place soon after emergence, and the female 

 drops its eggs in the water and soon perishes. Some species 

 emerge in early spring before the snow is off the ground, and the 

 small, dark, ahnost black flies may often be foTind on the snow. 

 Very little is known regarding this order of insects. Mnny species 

 undoubtedly exist in our r>lear, flowing streams, and as the nymphs 

 are easy to rear the study of them should not be neglecte"^. As 

 different species occur throiighout the season the study of the 

 seasonal forms should prove extremely interesting. 



The Dragon flies fOdonata) have long been objects of fear 

 especially to children. "Sew up your ears". "Devils' darning 

 needles", "snake doctors", etc., are names which terrified us in 

 our youth and with what frantic haste we would scramble away 

 from a pond or stream where these dreadfiil animals occurred. 

 Despite all this slander and superstition, the Dragon flies are not 

 only entirely harmle.ss but are our best friends. The nymphs 

 occurring in every pond are voracious feeders, destroying many 

 mosquito larvse, "wrigglers", while the adults feed largely upon 

 gnats, etc. The n;vmphal life lasts two or three years and is spent 

 in sluggish ponds, where there is an abundant food supply. The 

 nymphs of Dragon flies have a wonderful breathing apparatus, 

 the rectal portion of the intestine being modified into a tracheal 

 gill. Water is sucked into the chambers and the oxygen is taken 

 up by the small tracheoles. The water can be ejected at wnll with 

 considerable force and aids materially in propelling the nymph. 

 In the Damsel-fly nymphs the tip of the abdomen bears three leaf- 

 like gills which serve for breathing. The nymphs of both Dragon 

 flies and Damsal flies exhibit many wonderful adaptations and 

 deserve careful study. The fauna, particularlv the insect fauna 

 of the Maritime Provinces, has been sadly neglected and surely 

 the time is rijie for more concerted effort, even though our efforts 

 result only in the collecting and labeling of species. 



The Caddis-flies (Trichoptera) offer a very interesting fleld for 

 study. The case- building species are numerous in all oiir ponds 

 and streams, and the wonderful houses that they build may well 



