9 



period. Immediately after molting they are very light green- 

 ish or grayish and their characteristic color-pattern is beauti- 

 fully distinct, but they gradually darken and the coloration 

 becomes more and more obscure until, as the time for the next 

 molt approaches, it is almost entirely lost and the nymph be- 

 comes uniformly dark and dingy. 



When grown, the nymphs seek the shore or some floating 

 object and clamber up a little way on standing vegetation, logs, 

 tree-trunks, sticks, bridge-piling, the sides of boats, or the like, 

 and, fixing their feet firmly, i3roceed to transform to the im- 

 ago stage. Transformation mostly takes place very early in the 

 day and is largely over w^ith by nine o'clock, although scatter- 

 ing emergences may occur at any time. The usual process will be 

 fully described under Traniea Jacerdta. The adults scatter con- 

 siderably, but a large number remain in the original vicinity, 

 busily ovipositing for a new brood of nymphs. A short but 

 undetermined period elapses before egg-laying begins. 



Oviposition is of two kinds, endophytic and exophytic. 

 That of the groups with more slender nymphs, Zygoptera and 

 yEscJinidit, is endophytic. They have an elongated egg, which 

 is inserted by means of an ovipositor into living or dead vege- 

 table substances, either resting in water or at least moist. 

 The female immerses the tip of her abdomen or enters the 

 water completely. She usually succeeds in escaping safely 

 from it, but is sometimes rescued by the male (Todd, '85). The 

 oviposition of the groups with broader nymphs, Gomphidie, 

 Cordulegasteridif, and LihelluJidw, is exophytic. Their eggs 

 are shorter and oval, and are extruded in a gelatinous matrix. 

 The female dips her abdomen in the water, usually during 

 flight, releasing at each dip a number of eggs, which sink to 

 the bottom or lodge on the vegetation. Sometimes, when too 

 hotly pursued by males, she will alight on water moss or drift- 

 wood and cast her eggs loose there. In the case of Lencorli'mia 

 this is apparently the usual method of oviposition. In some 

 cases the eggs may be deposited on moist mud [Diplax, Soinaf- 

 ochlora) or affixed to the bank or to water plants. The female 



