No. 39] ODONATA OF CONNECTICUT I3 



Libellula pulchella, and Lihellula semifasciata, which takes place 

 northwards in spring and southwards in fall. Mr. C. R. Ely 

 reports that he has witnessed the migration of dragonflies several 

 times at his summer home in East River, Conn., the migrating 

 insects being collected in a dense swarm, and moving along the 

 sea coast. 



Howe (1921, p. 132) came to the general conclusion that the 

 distribution of a species should be stated "in both geographical and 

 ecological terms," and that a species "may inhabit one or more, 

 often three zones, and even two regions as defined by Merriam." 

 It is thus important in determining distribution to note what is 

 the nature of its environment if progress is to be made in our 

 knowledge of the limits of its distribution. At present little is 

 known concerning the factors governing a given species' range, 

 but there are doubtless ecological conditions which control this 

 phase of activity the same as for plants or other animals. In 

 other words, distribution is a function of temperature, moisture, 

 sunlight and other conditions, which depend in turn on altitude, 

 latitude and the like. Food of the nymphs, conditions of the 

 water as regards contamination, the amount of movement in the 

 water, air temperature, and many other factors determine whether 

 a species will be found in a given locality. To attempt to deter- 

 mine whether the necessary ecological conditions exist in Con- 

 necticut for each species is obviously impossible, but to compen- 

 sate for our lack of knowledge along this line, many species have 

 been included which have been captured in neighboring states. 

 The chances that species not included in this article will be found 

 in the state is thereby lessened considerably, though of course 

 importations from long distances may occur. 



Emergence from the water usually takes place late in the after- 

 noon or evening, or early in the morning, though a great deal 

 depends on the location. Damsel flies emerge throughout the 

 day, and require only a few hours to develop enough to fly. The 

 Anisoptera require longer, but even they are ready to begin the 

 hunt again in an incredibly short time. Many species, however, 

 do not obtain their full coloration until some days afterwards, and 

 individuals thus immature are known as teneral. 



The food of adult Odonata consists of small insects such as 

 mosquitoes, gnats, beetles and moths. The larger Aeshnids are 

 particularly active feeders and may be seen to capture insects of 

 considerable size. Some species have been known to feed success- 

 fully on honey bees. 



The nymphs of all species eat other insects, mainly the larvae 

 of small Diptera, but the younger nymphs subsist on protozoa and 

 Crustacea, such as Clodocera and Copepoda. Probably others of 

 the smaller groups are also eaten. We thus find the damsel fly 

 feeding upon mosquito wrigglers in the later nymphal stages and 



