44 A VENATIONAL STUDY OF THE ZYGOPTERA 



i6 (15). Area of hind wing posterior to Cu2 narrower, with two to four rows of cells 



between end of Cu2a and wing margin which is not very convex; hind wing about 



three and one-half times as long as broad. Rs not usually so strongly waved as 



■ to cut off an anterior sector 17 



17 (18). M2and Msnot appearing forked. Most cells of basal space divided into 

 two by median nervules. All four wings of male opaque. Cu2a alike in fore and 

 hind wings. Japan and southeastern Asia to India. (Fig. 13.) 



Matrona Selys, 1883 



18 (17). Mo and M3 appearing forked because of attached sectors. Only one or two 

 cells of basal space divided. Front wings of male hyaline. Cuoa in fore wing 

 tends to parallel A. Malaysia. (Fig. 14.) Neurobasis Selys, 1863 



19 (2). Cu2a turning away from the wing-base; the sector from Cu2a toward the anal 

 angle shorter than the quadrangle 20 



20 (23). True stigma present. M1+2 fusing with R at least in the hind wing. Mi-s 

 and M4 arise separately from arculus. Asian genera 21 



21 (22). Quadrangle approximately as long as the basal space and with four to seven 

 cross-'veins; posterior wing-margin near the anal angle not concave. Stigma 

 about three times as long as broad ; the distance from the wing-base to the nodus 

 more than two-fifths of the wing length. Posterior end of the medio-anal link 

 more basal than the anterior end. China and Japan. (Fig. 15) 



Mnais Selys, 1853 



22 (21). Quadrangle one and one-half times as long as the basal space and with ten 

 or more cross- veins; posterior wing-margin near the anal angle very concave. 

 Stigma four times as long as broad; the distance from the wing-base to the nodus 

 less than two-fifths of the wing length. Posterior end of MA not so basal as 

 anterior end. China and Formosa. (Fig. 16.) . .Psolodesmus McLachlan,i870 



23 (20). Stigma present or not. Mi+2 not fusing with R. Mi-sand M4 usually arise at 

 a common point, especially in the hind-wing. Rs in the hind wing waved so as 

 to approach M2 very closely. Africa and Madagascar. (Fig. 17) 



Phaon Selys, 1853 



24 (i). Cu2a not present. Area posterior to Cu2 supported by a wide bend of Cu2. 

 Rs in the hind wing not strongly waved. Quadrangle often very convex anter- 

 iorly and widened distally. Arculus not angled, but oblique 25 



25 (26). Basal space free. M2, M3, Cui, and Cu2 with attached sectors. Veins and 

 sectors turn sharply toward wing margin. Quadrangle almost as long as the 

 basal space. India to Malaysia. (Fig. 18.) Vestalis Selys, 1853 



26 (25). Basal space crossed, distinctly longer than the quadrangle. Sectors inter- 

 mediate, generally not attaching to the main veins. Veins and sectors not bend- 

 ing sharply toward the wing-margin. Rs and M3 parallel at the end, with two 

 intervening sectors. Genera of the Western Hemisphere, ranging from Canada 

 to South America. (Figs. 19 and 20.) 



Heterina^ Selys, 1853, and Lais Selys, 1853 



