24 



FIRST LESSONS IN ZOOLOGY 



ous wing-pads ; the larger these are the filder is the 

 n)-mph, and the more nearl)' read)' tu cliange into the 

 adult form. April and Ma}- are the best months for col- 

 lecting nj'mphs because the oldest ones found then are 



nearly ready to change into 

 winged flies, and this they 

 may do in the schoolroom. 

 A careful observer of these 

 creatures gives the following 

 directions for bringing the 

 nj'mphs to maturit)-. " Place 

 them [the collected nymphs] 

 in a wooden pail or tub. If 

 the sides arc so smooth that 

 they cannot crawl up to 

 transform, put some sticks 

 in the water for them to 

 Tie mosquito 

 netting tightly over the top, 

 or better, make a screen 

 cover; leave three or four inches of air between the 

 water and the netting ; feed at least once a week ; set 

 them where the sun will reach them ; and after the ad- 

 vent of warm spring weather look in on them early every 

 morning to see what is going on.'' 



To feed the nymphs provide them with smaller live 

 insects. Mosquito wrigglers, Ma)--fl3- nx'mphs, small 

 water-bugs, and any tiny swimming "beastics " that can 

 be caught in stagnant water should be dropped alive into 

 the tub. The nymphs, like the adult dragon-llies, are e,\- 

 clusivcl}- carnivorous in diet. ()bser\e how the)' catch 

 their prey. Note that the)- rarely come to the surface ol 

 the water, and that there is no indication of breathing. 

 In fact the)- breathe under water b\' means of gills which 

 are not external, but which line the posterior third of the 



Fig. 12.— The ydunf; (nymph) uf :i crawl Out On. 

 (lra£(on-fly. (From Jenkins and 

 Kelhjgg.) 



