274 Phylum Art hr op oda 



REARING FALL AND WINTER PLECOPTERA* 



T)ECAUSE of their habit of congregating in places exposed to the 

 O warming influences of the sun's rays, most of the fall and winter 

 stonefly adults are easy to capture. During the warmer days of late 

 fall and early winter they are likely to be found crawling about on ex- 

 posed tree trunks, fence posts, or rocks located close to a stream inhabited 

 by the nymphs, particularly if these objects are covered with an algal 

 growth. 



In spite of the general belief that most adults of stoneflies do not feed, 

 all of the fall and winter stoneflies of the Oakwood, Illinois, region have 

 been found to feed. On many occasions the adults of Taeniopteryx 

 nivalis, Allocapnia recta, A. vivipara, A. mystica, and A. granulata were 

 observed feeding upon blue-green algae (Protococcus vulgaris) growing 

 on tree trunks, fence posts, and stones near the habitat of the nymphs. 

 A single specimen of T. parvula was also seen feeding on algae on a tree 



trunk. 



Eggs have been obtained by the simple expedient of catching females 

 with egg masses and submerging them in water. The egg mass soon 

 falls from the female and the individual eggs separate and settle to the 

 bottom of the dish. 



Simple methods have sufficed for rearing fall and winter stoneflies. 

 Fullgrown nymphs are collected and kept alive in small tins containing 

 moist leaves until the emergence of the adults. In order to observe closely 

 feeding, mating, and egg-laying habits, the adults may be kept alive and 

 healthy in small hermitically sealed aquarium jars containing a layer of 

 moist sand, a supply of bark bearing a good growth of green algae, and 

 old leaves and stems on which the adults may run around or in which 

 they may hide or rest. The eggs will hatch in glass tubes covered at both 

 ends with fine bolting and submerged in unpolluted streams. No doubt, 

 if supplied with the proper quality and quantity of food, the nymphs 

 will develop under the same conditions.** 



The nymphs of Taeniopteryx and Allocapnia, both young and nearly 

 grown, are herbivorous. No doubt a few protozoans are occasionally 



♦Abstracted from an article in III. Nat. Hist. Bull. 18: 345. 1929, by Theodore H. 

 Frison, Illinois Natural History Survey. 



** Editor's Note: Lucy Wright Smith, of Cornell University, reported in Ann. Ent. Soc. 

 Amer. 6:203, 1913, the use of essentially these same methods for Perla immarginata. 

 Adults were kept in small wire cages and mating and egg laying occurred readily in 

 captivity. These nymphs are carnivorous, however. Black fly larvae and mayfly nymphs 

 proved satisfactory as food. . . 



By these same methods adults of Pteronarcys have been obtained and kept in captivity 

 where mating takes place readily. Eggs obtained from these or from wild adults have 

 been taken in June and have hatched in running water the following February. Due 

 undoubtedly to a lack of the proper food, however, these newly hatched nymphs were 

 not reared. Older nymphs eat well decayed leaves. M.E.D. 



