54 A VENATIONAL STUDY OF THE ZYGOPTERA 



5 (4). Four antenodal cells between M4 and Cui. The arculus between the first 

 and second antenodals, much before the second. West Africa. 



Mesocnemis''^ Karsch, 1891 



6 (3). The upper side of the quadrangle not more than three-fourths the length of 

 the lower side; the antenodal cells three or less between M4 and Cui. Ac gen- 

 erally beyond the level of the first antenodals. Antennae not as above except in 

 Platycnemis and Stenocnemis 7 



7 (10). Cuo long, extending beyond the level of the base of Mia which is six to seven 

 cells before the level of the stigma. Postnodals fifteen or more. Posterior 

 tibiae of males not dilated, superior anal appendages at least as long as the in- 

 ferior 8 



8 (9). Three antenodal cells between M4 and Cuj. About fifteen postnodal cells in 

 the front wing. The third segment of the antenna shorter than the first plus the 

 second. Cuo long, extending beyond the level of the base of ^NIi^, which vein arises 

 six to se\-en cells before the stigma. India to Burma. (Fig. 72.) 



Calicnemis Selys, 1S63 



9 (8). Two antenodal cells between JVI4 and Cui. Front wing with eighteen to 

 twenty postnodals. The third segment of the antenna longer than the first plus 

 the second. West Africa Stenocnemisi^ Karsch,_ 1899 



10 (7). Cu2 not extending beyond the level of the base of AIu, the latter arising two 

 to four cells before the stigma. About thirteen postnodals. Two antenodal 

 cells between M4 and Cui. Posterior tibiae of males more or less dilated, su- 

 perior anal appendages shorter than the inferior 11 



11 (12). Cu2 extending almost to the level of the base of Mia. The second antennal 

 segment as long as the third. Syria to Japan and Sumatra; Madagascar.. 

 (Fig. 73-) Copera Kirb>-, 1 890 



{Psilocnemis Selys, 1863) 



12 (11). Cu2 not extending to the level of the base of Mia by several cells. The third 

 antennal segment as long as the first plus the second. Mediterranean Region and 

 China. (Fig. 74.) Platycnemis Charpentier, 1840 



13 (2). Wings petioled close to or beyond Ac; R^ usualh' arising beyond the sub- 

 nodus (sometimes at the subnodus in AUocneiftis) 14 



14 (21). R3 arising within one or two cells of the subnodus 15 



15 (20). Wings not petioled to the level of the arculus. Ac almost as near the level 

 of the second antenodal as of the first 16 



16 (17). The end of the wing with a denticulate margin. Superior appendages of 

 the male longer than the inferior, which are straight. Malaysia. (Fig. 75.) 



Idiocnemis Selys, 1878 



17 (16). The end of the wing not denticulate at the margin. Superior appendages 

 not longer than the inferior 18 



18 (19). The upper side of the quadrangle not more than three-fourths the length of 

 the lower. Cu2 extending beyond the subnodus to a distance of thirteen to six- 

 teen cells. Usually six to nine cells between the base of R, and the point where 

 M,-|-2 forks. India to Malaysia. (Fig. 76.) Coeliccia Kirby, 1894 



{Trichflcucniis Selys, 1857) 

 " Description only was available for this genus. 

 " Studied from descriptions only. 



