Plecoptcra 2 73 



laboratory. During the first instar no food was given ; during the second 

 and third stages Paramecium and small mosquito larvae formed the food. 

 The remaining stages fed upon mosquito larvae and small crustaceans 

 until the tenth instar, when pieces of earthworms and mayfly larvae were 

 supplied. In the eleventh instar small fish were eaten. The individuals 

 were kept in separate dishes after the third instar on account of cannibal- 

 ism. 



Order plecoptera 



REARING THE STONEFLY, NEMOURA VALLICULARIA* 



THIS herbivorous stonefly is an inhabitant of clear-flowing cold spring 

 brooks in the eastern United States. Adults appear on the wing in 

 the latitude of Ithaca, N. Y., about the middle of March and disappear 

 about the middle of April. They live among the vegetation of the brook- 

 side where they run about actively and make short flights when the sun 

 shines warmly about noon. They eat sparingly of the young leaves of 

 wild Touch-me-not (Impatiens). They are able to survive without food 

 for several days. 



About a week after transformation they reach sexual maturity and 

 mate about midday. After mating, the females live for about a week, 

 hiding in shaded places, and depositing gelatinous clumps of whitish eggs, 

 numbering about 150 to 200 each. 



To obtain eggs for rearing, adults of both sexes were confined in a 

 small box with porous bottom, so placed that it rested on the surface 

 of the brook. This insured high humidity. Leaves of wild Touch-me- 

 not were added for food, and blocks of decayed wood were placed inside, 

 supported on slender twigs. The eggs were deposited on the under side 

 of these blocks. 



Newly hatched nymphs were isolated in numbered shell vials, closed 

 at the mouth with silk bolting cloth. These vials, assembled in an 

 enameled tray, were immersed in the bed of the brook. They were ex- 

 amined each day for cast skins. For food the nymphs were supplied 

 with bits of decaying elm leaves. The vials were cleaned and the food 

 was renewed once a week. 



Twenty-two instars were recorded during the nine months of develop- 

 ment from hatching on the 2nd of July until emergence on the 29th of 

 the following March. 



j. G. N. 

 r 



♦Abstracted from an article in Lloyd Library Bull. 23, 1923 (Ent. Ser. No. 3) by 



Chen-fu Francis Wu, of Yen Ching University, Peiping, China. 



