18 



satjanus), and the common perch [Perca flavescens). The latter is 

 anabundant species in the small northeastern lakes of the state. 



Befosfoma, Ranatra, Nofo}iecf(t, and the like, according to 

 Mrs. Aaron (Lamborn, '90, p. 50), prey on young nymphs, and 

 she also mentions a small red mite and a minute dipteron as 

 parasitic on the eggs of OdoiKtta. Mr. Needham ('98) has 

 recorded the finding of numbers of nymphs in the stomachs of 

 herons, and he once found the intestine of a nymph parasitized 

 by very large Gregar'niidie fully 1 mm. long. 



Emerging imagos while limp and pale are the easy prey of 

 even their weakest enemies, and great decimation takes place 

 among them at this time. Ants, spiders, robber-flies, frogs, and 

 birds eat many of them. 



The full-fledged dragon-flies devour the small insect life of 

 the air in vast quantities, especially gnats and mosquitoes, most 

 of which probably developed in the waters previously inhal)ited 

 by the dragon-fly nymphs. These seem to make little or no 

 attack upon the larval stage of the gnats and mosquitoes, as if 

 reserving them for their imago life. Dr. Lamborn, by offers of 

 prizes, started an investigation to determine the practicability 

 of artificially utilizing dragon-flies for the destruction of mos- 

 quitoes and flies; but the evidence published (Lamborn '90) 

 indicates that these pests may be dealt with more effectively 

 by direct measures, since the the attack of dragon-flies could 

 not easily be controlled and directed, although in their own way 

 and time they doubtless reduce the numbers of the pests very 

 considerably. 



Mature dragon-flies do not usually suffer seriously from 

 natural enemies. They are frequently found infested by small 

 red mites. Some birds, such as the king-bird, possess sufficient 

 alertness to capture them as regular articles of their food. It 

 seems to be the weaker forms, such as A(jrioN, that suffer thus 

 most extensively (Needham '98). The females while oviposit- 

 ing are sometimes captured by fishes. 



COLLECTING AND REARING. 



A careful consideration of the statements and suggestions 



