40 Journal New York Entomological Society. [Voi. xvii. 



two suborders, Zygoptera 142, Anisoptera 161, are much more nearly- 

 equal than in the northern region, where the Anisoptera are in much 

 greater excess. 



There are numerous interesting cases of replacement of similar 

 genera when we compare the two faunas. Thus among the Caloptery- 

 ginge the genus HetcEritia is represented in the central region by 17 

 species, while not more than 3 occur in the northern region. Calop- 

 teryx, on the other hand, has 8 northern species, while Calvert's list 

 contains only one. Among the Agrioninae, the genus Enallagma , 

 with more than 20 northern species, has but 5 representatives in the 

 central region, but this defect is more than balanced by the genus 

 Argia, which is represented in the central region by 48 species, while 

 but 8 occur in the rest of North America. In the Gomphinae, the 

 genus Gomphus, with some 35 northern species, is not found in the 

 central region, nor are the related genera, Ophiogomphns, Dromogom- 

 phus, Hagenius and Tachopteryx. However, there do occur Eplgovi- 

 phus and Gomphoides, not found in the northern region, and Progom- 

 phus and Erpetogomphus, each with a single northern representative. 

 The Corduligasterinse are scantily represented by two species, and of 

 the Cordulinae, of which there are about 40 species in the northern 

 region, the only undoubted record is that of a larva (species undeter- 

 minable) of a Macromia taken in northern Mexico. The Libellulinae 

 are, however, richly represented, with 28 genera and 97 species, of 

 which number 18 genera and 75 species do not occur in the northern 

 region. Our common northern genera, Celithemis (with 6 sp. ) and 

 Leucorhinia (6 sp.) have not been found in the central region, and 

 Sympetrum (17 sp.) and Libellula (20 sp.) are represented respec- 

 tively by 2 and 8 species in the central region. On the other hand, 

 Micrathyria (9 sp.) and Brec/unorhoga (9 sp. ) do not occur in the 

 northern region, and Erythrodip/ax {^i'^ sp. and var. ) is represented 

 scantily in southern United States, while one species {E. berenice~) 

 ranges coastwise as far as Massachusetts. 



Naturally, Calvert has found it necessary to do a great deal of 

 revising in connection with this work, yet with commendable con- 

 servatism, he has chosen to give us but two genera, Hesperagrion and 

 Metaleptobasis, both belonging to the Agrioninae and neither of them 

 including any northern species. It was to be expected that many 

 new species would appear in a region so little studied previously, but 

 one is scarcely prepared to meet with such a number, 81, until he 



