44 DKAGON FLIES VS. MOSQUITOES. 



The third group, with the genera Gomphus* and Anaxf 

 of the a'Eschnina, and Cordnlia, Traniia, Libellula,* Di- 

 plax,* etc., of the LibeUulina, is far the most diversified 

 in its habits and numerous in both species and individ- 

 uals. These dragon flies are nearly as swift on the wing 

 as ^schna, l)ut not capable of the sustained and lofty 

 flights. Sunset finds most of them safely ensconced for 

 the night, and they do not leave their dew bespangled 

 couches as early as either the ''hammer heads" or "high 

 fliers." In their methods of oviposition there is but little 

 latitude for variation. Uhler (Packard ^'^) has observed 

 Libellula auripennis drop a bunch of eggs while balan- 

 cing herself just above the surface of the water, and tiie 

 same insect he has seen settled upon the reeds in brackish 

 water with her abdomen submerged and there attach a 

 cluster of eggs. Others of the same genus fly at the 

 water with a dash, striking the end of the abdomen, and 

 deposit eggs on the surface. Todd,^*'- calling attention to 

 this habit in a species of ^schna, suggests that it may 

 serve as a bath to rid them of parasites. Davis,-'- Dunn,-^ 

 Weir,^"*^ Todd,^^2 and Aaron ^ have all noted the habits 

 of various species which go beneath the Mater for some 

 distance. Todd has seen a Libellula remain under water 

 for half an hour depositing eggs on a stem. M'Lach- 

 lan^^ has called attention to Agrion mercuriale with a 

 part of the abdomen incrusted with mud, caused by sink- 

 ing its eggs in the mud left from dried up pools. Pack- 

 ard has observed Perithemis domitia depositing its eggs 

 on floating refuse on a pond. Lacase-Duthiers is quoted 

 by Packard,^''* as authority for the fact that the Agrions 



* See Plate VI., Figs. 4, 1, and 2. 

 t See Plate I., Fig. 1. 



