NEW OR HITHERTO UNKNOWN EPHEMERID 

 NYMPHS OF THE EASTERN UNITED 

 STATES. 



EDWARD W. BERRY. 



The nymphs of these, our most primitive Neuroptera, are 

 especially interesting because of their varied and great speciali- 

 zation, each species having solved the problem of existence in 

 a somewhat different manner. The described nymphs are few. 

 That of Bcetisca obesa Say has been known and figured for 

 some years. Needham, 1 in 1901, describes the nymphs of 

 seven species, representing as many genera, from the Adiron- 

 dack region ; and a number of undetermined American nymphs 

 are described and figured in Eaton's monograph. It is singular 

 that these most interesting aquatic larvae are so little known. 

 They are very easy to rear and form a delightful addition to 

 any aquarium. Almost any pond or stream, of whatever size, 

 will furnish its quota of forms, and there is a constant succes- 

 sion of species throughout the year. Thus I found Blastimis 

 cupidus extremely common during the latter part of March and 

 the first part of April, while diligent search on May 17 failed 

 to disclose any specimens. Habrophlebia americana was 

 abundant during the last week in May, while on June 14 I 

 could not find any trace of it. 



In these brief notes special attention is directed to the 

 structure of the gills, because they afford a convenient and 

 admirable criterion of the relations of the various species, 

 both to one another and to their environment, and will prove 

 exceedingly useful as a basis for phylogenetical hypotheses 

 when more extended observations have been accumulated. 



I am greatly indebted to Nathan Banks of the Department 

 of Agriculture for authoritative determinations of the imagos. 



l N. Y. State Museum, Bull. No. 



