DRAGONmES AND DAMSELFLIES IN PONDKISH CULTURE. 21 5 



Food of Damselfly Imagos, Fairport, Iowa, 1916 — Continued. 



Enallagma hageni — Continued. 

 Diptera — Continued . 



Dolichopodid fly Captured while eating. 



Anthomyiid fly Do. 



Syrphid fly Do. 



Simulium vittatum Taken from mouth. 



Undetermined flies : In alimentary canal. 



Palpomya, sp Captured while eating. 



Nematocera, sp Garman, 1917, p. 445. 



IvCpidoptera — Ancyloxcypha numitor Captured while eating. 



Odonata — 



Ischnura verticalis Do. 



Enallagma, sp. (dead) Seen eating. 



Ischnura verticalis: 

 Diptera — 



Midge, Orihocladius, sp Captured while eating. 



Grass-stem fly, Geomyzidae Do. 



Midge, Chironomus, sp Do. 



Undetermined Do. 



Lepidoptera — Butterfly Garman, 191 7, p. 445. 



Ischnura kellicotti: Diptera — Undetermined Williamson, 1899, p. 280. 



Lestes vigilax: Diptera, Nematocera Garman, 1917, p. 445- 



Argia mxsta putrida: 



Coleoptera — Beetle, Berosus siriatus Captured while eating. 



Hphemeridae — 



Mayfly — Calliabeies, sp Do. 



Mayfly — Hexagenia, sp Do. 



Hemiptera — Plant louse, Aphis, sp Do. 



Diptera — Undetermined flies In alimentary canal. 



Argia apicalis : Diptera — Nematocera Garman, 1917, p. 445. 



Enallagma civile and E. aniennatum: Diptera — Nematocera. Do. 



Generai. Statement. — Williamson (1899, p. 235) has given one of the best general 

 statements. 



The food of the imagos consists almost entirely of other insects, though some are known to occa- 

 sionally eat the flesh of dead animals. Of the insects eaten Diptera are more preferred than any other 

 order, though all soft-bodied insects seem to fall a prey to their ravenous appetites. Larger species 

 eat their smaller relations. Leaf hoppers and other Hemiptera and Lepidoptera are consumed. 



The above statements very strongly substantiate Williamson's statement that the 

 Diptera form a favorite food. Every odonate species included in them, with one 

 exception, has eaten Diptera of some sort. And, curiously enough, all we know about 

 the food of this one exception, Dromogomphtts spoliatus, is derived from Williamson 

 himself. Some of the species, such as Anax junius and Enallagma hageni, show a decided 

 preference for flies and midges. The statement that the larger species eat the smaller 

 ones is also well verified, even among the damselflies. 



Williamson also recorded on the same page that he once captured a dragonfly hold- 

 ing a large wasp in its mandibles. There were two wasps in Poulton's list of the prey 

 of the Odonata (1906, p. 399), and honeybees were included in Campion's list (1914, 

 p. 499). The English paper Field for March 21, 1908 (p. 486), mentioned a bee keeper 

 in Australia who complained that the dragonfly destroyed more of his bees than any of 

 the birds. None of these records were American, but they serve to indicate that our 



