6 



covered the Goinphidd' and Cordulegasterid(e, his second ('81) 

 the ^"EscluiuJit, and his third ('90) the SyntheiHi'nut and Cor- 

 duliiiKt and also Trainee and Faidala. Hagen ('85 ) gave a greatly 

 extended revision of the two families previously treated by 

 Cabot ('72). The large and abundant family LiheUulidce was 

 not treated by them. Karsch ( '93) gives descriptions, figures, and 

 keys to West African nymphs. The characters assigned to the 

 major groups in his keys are, as Dr. Calvert has pointed out, 

 only locally or partially true. Lucas ('97, '97a) has described 

 and figured a few English nymphs, and Roster ('86, '88), a num- 

 ber of Italian Zijgoptera. Beutenmiiller ('90c) has given a 

 bibliography of nymphal descriptions, excepting those in Cabot's 

 '90. Needham ('97a, '99) gives suggestions on collecting and 

 rearing nymphs. 



Among the general works. Dr. P. P. Calvert's admirable 

 paper ( '93 ) deserves first mention. It includes a complete and 

 accurate summary of all the more important biological and 

 anatomical details concerning dragon-flies and their nymphs, 

 with generic keys for both. Descriptions are given of the 

 species of the region about Philadelphia, among which are 

 most of our commoner forms. The phylogeny of the dragon- 

 flies in general, with especial reference to the structure of the 

 gizzard, is discussed in a scholarly article by Dr. F. Ris ('97). 



The principal monograph of American species is in Hagen's 

 well known "Neuroptera of North America" ('61). A num- 

 ber of monographic papers have been published by Dr. Selys- 

 Longschamps in Belgium. The best catalogue of species is 

 that of Kirby ('90). It contains several surprising changes in 

 nomenclature, one of which — the use of .Eshna in place of 

 Gontplius — is fortunately not well founded. Banks ('92) has 

 listed the American species, and given a key to the genera. 

 From an economic point of view, especially as to their utility 

 as destroyers of obnoxious Biptera, dragon-flies are treated in 

 Lamborn's collection of prize essays ('90). 



The numerous published lists of Odoiuda in this country 

 contain much valuable information as to the life history of our 



