60 A VENATIONAL STUDY OF THE ZYGOPTERA 



89 (94). Stigma in fore and hind wings of males dissimilar in color, size or both 

 Tenth segment of abdomen of male generally with a bifid dorsal process. Fe- 

 male often with apical spine to segment eight of abdomen. Postocular spots, in 

 female at least, tend to disappear. Females dichromatic or polychromatic. . . .90 



90 (91). In the male the stigma of the front wing does not touch the costa. Fe- 

 male with no external black stripe on second or third tibiae. Coloration black, 

 orange, and yellowish. Postocular spots, in females at least, tend to disappear. 

 United States to Venezuela and West Indies. (Fig. 97.) 



Anomalagrion Selys, 1857 



91 (90). Stigma in male touching C. Female generally with an external black 

 stripe on second and third tibiae 92 



92 (93). Penis with pair of erect spines on the penultimate segment. In American 

 species at least, the anterior surface of thorax not solid black. Cosmopolitan. 

 (Fig. 100.) Ischnura Charpentier, 1840. {Mkronympha Kirby, 1890) 



93 (92). Penis with pair of erect spines on penultimate segment. Anterior surface 

 of thorax solid black, except in green females, middle prothoracic lobe with small 

 tooth. on each side. Arizona to Baja California. (Fig. loi.) 



Celaenura Kenned>-, 1917 



94 (89) . Stigma in fore and hind wings of male similar 95 



95 (102). The second antenodals distinctly before the level of the arculus. Both 

 wings not petioled to Ac, but the vein from Ac back to the wing-margin, that is 

 A', does not continue the direction of the petioled part of the margin, instead it 

 passes up toward Ac and Ab 9^ 



96 (97)- Female with apical spine on segment eight. Postnodals six to seven. 

 Coloration dark bronze, with yellow and blue. Dichromatic temales. A genus 

 of the New World — tropical America and the West Indies. (Fig. 102.) 



Ceratura Selys, 1876 



97 (96)- Female without apical spine. Old World genera 98 



98(101). Postnodals five to nine; females dichromatic; very small insects, usually 



less than 24 mm. long 99 



99 (100). Quadrangle of fore wing with upper side less than half as long as the lower 

 side; hence distal angle very acute. Legs very long in comparison with rest of 

 body. Australia. (Fig. 103.) Austrocnemis Tillyard, 1913 



100 (99). Quadrangle of fore wing with upper side one-half or more than one-half 

 of length of lower. Legs short. Australia to India. (Fig. 104.) 



Agriocnemis Selys, 1869 



loi (98). Postnodals ten to twelve; females not dichromatic; chiefly insects of more 



moderate size i.e. abdomen of twenty-five or more mm. India to Australia, 



and in Zanzibar and Madagascar. (Fig. 105.) . . . . Argiocnemis Selys, 1877 



102 (95). The second antenodals not distinctly before the arculus, or it so, either one 

 wing petioled to Ac or the vein A' continues direction of the hind margin of wing 

 up to point of petiolation 103 



103 (i 16). Both wings distinctly not petioled to the le\el of Ac 104 



104 (in). Female without apical spine to segment eight 105 



