272 Phylum Art hr op oda 



the slowly moving N. belia carried constantly served as a part of the 

 food supply of the small Crustacea or of the still smaller animals (In- 

 fusoria, rotifers) on which the Crustacea fed. 



Almost identical methods were employed in rearing a larva of Anax 

 Junius* up to the time when it reached a length of 28 mm. It, the water in 

 which it had been living, Lemna and other plants, were then transferred 

 from the finger bowl to a battery jar, 145 mm. in diameter and 160 mm. 

 high, and covered with a sheet of glass as before. A stick of wood was 

 leaned against the side of the jar to give the larva an object on which to 

 climb. It was there that its final exuviae was found. 



For the earlier stages small Crustacea were the chief food; when 5 mm. 

 long, Culex and Anopheles larvae, small corixids, Daphnia, and mayfly 

 larvae were used. During the final months the last named, especially 

 those of the genus Heptagenia, were almost the only food given. A . Junius 

 seemed to pay no attention to Asellus. 



Nevin f reared Sympetrum vicinum from egg to adult in stender 

 dishes. During the first instar specimens from a protozoan culture were 

 placed in the dishes. This culture proved to be mainly of Paramecium 

 aurelia which were so small that the larvae did not seem to notice them 

 and continued to die, probably from starvation. When Paramecium 

 caudatum were fed the larvae ate them greedily. Another mixed culture 

 used at this time contained many Stylonychiae and a few Vorticellae, 

 although the larvae were never seen to eat the latter except with Daphnia 

 to which Vorticellae were attached. Several ostracods of the family 

 Cyprididae were eaten before the first molt. Later larger ostracods and 

 copepods, including Cyclops and Diaptomus, were eaten. The copepods 

 proved more proficient in capturing Paramecia than the dragonfly larvae 

 and had to be removed until the larvae were larger. They also destroyed 

 the exuviae of 5. vicinum or parts of them if the latter were left too long 

 after the individuals had molted. During the last few instars Daphnia, 

 Hyalella, and small mayfly and stonefly larvae were fed. Daphnias were 

 not eaten from choice, but formed an important part of the food, espe- 

 cially when mayfly larvae were not at hand. All larvae were fed and 

 cared for three times a week. 



Miss Laura Lamb,$ in rearing Pantala flavescens, removed the larvae 

 soon after hatching from the dish in which the eggs were laid and placed 

 them in small stender dishes which were kept in a shaded part of the 



♦Editor's Note: Freshly laid eggs of Anax Junius may easily be obtained by setting a 

 stem of cat-tail (Typha) in a place to attract ovipositing females. It should be set aslant 

 in the surface of the open water several yards out from, the pond margin. It will then 

 have preference over stems at the margin (where, presumably, enemies may lurk). If 

 a fresh stem be used each day, the eggs may be dated. J. G. N. 



t Trans. Amer. Ent. Soc. 55:79, 80, 1929. 



X Trans. Amer. Ent. Soc. 50:289, 1924. 



