LIBELLULID^. 599 



species of Libellula, however, during oviposition, tlie male 

 retains bis liold on the neck of the female, and both fly over 

 the surface of standing water, the female touching the surface 

 of the pool with the tip of her abdomen, and letting the eggs 

 fall into the water. 



"In some genera (Libellula, Agrion) the two sexes of a spe- 

 cies differ greatl}- in color, the males having bright variegated 

 colors, while the females are dusky, being more of one color. 

 The males of many species have, on the abdomen, several days 

 after exclusion from the pupa case, a bluish powdery exuda- 

 tion. The genus Calopteryx and allies dilfer sexually in the 

 color of the wings." (Gerstaecker.) 



"Brauer indicates the occurrence of dimorphism in the fe- 

 males of some species of the genus Neurothemis, some of 

 them having the wings very richly veined, as in the males, 

 whilst others have widely netted veins like those of the ordi- 

 nary Libellulffi." (Giinther's Zoological Record for 1<S67,) 



During July and August the various species of Libellula and 

 its allies most abound. The eggs are attached loosely in 

 bunches to the stems of rushes and other water-plants. In 

 laying them, the dragon-fl^', according to Mr. P. R. Uhler's 

 observations, "alights upon water-plants, and, pushing the 

 end of her body below the surface of the water, glues a bunch 

 of eggs to the submerged stem or leaf. Libellula aiirij^ennis 

 1 have often seen laying eggs, and I think I was not deceived 

 in my observation that she dropped a bunch of eggs into the 

 open ditch while balancing herself just a little way above the 

 surface of the water. I have also seen her settled upon 

 the reeds in brackish water with her abdomen submerged in 

 part, and there attaching a cluster of eggs. I feel pretty sure 

 that L. auripennis does not always deposit the whole of her 

 eggs at one time, as I have seen her attach a cluster of not 

 more than a dozen small yellow eggs. There must be more 

 than one hundred eggs in one of the large bunches. The eggs 

 of some of the Agrions are bright apple-green, but I cannot 

 be sure that I have ever seen them in the very act of oviposi- 

 tion. They have curious habits of settling upon leaves and 

 grass growing in the water, and often allow their abdomens to 

 fall below the surface of the water. Sometimes they fly against 



