20 A VENATIONAL STUDY OF THE ZYGOPTERA 



and Platycnemis and Coefiagrion on the other is hardly great 

 enough to merit their being placed in separate subfamilies, but it 

 may be done, if it is kept in mind that the groups are close to each 

 other and that the second is an offshoot from the first. 



So much may suffice for a discussion of the Megapodagrioninae; 

 those groups to which it has given origin may now be discussed. 



The Pseudostigmatinae 



As here used, this subfamily includes the Anormostigmatini of 

 Kirby's Catalogue, and is characterized by a diffusion of the stigma, 

 by having Mia parallel to M2 rather than to Mi, and by a very re- 

 tracted nodus with a long postnodal portion which has many cross- 

 veins and with the longitudinal veins running far out into the wing. 

 These insects are as specialized in a venational way as in their 

 elongate abdomens and peculiar habit of life, the nymphs living 

 in the small pools in epiphytic Bromeliads. If it were not for the 

 genus Thaumatoneura (fig. 51) they would stand so far removed 

 from all other Zygoptera as perhaps to deserve a separate family. 



Megaloprepus (fig. 46), however, the most generalized of the five 

 genera, has so many points of similarity to Thaumatoneura that 

 there can be no doubt of their relationship. They agree in the 

 width and general proportions of the wings, in the presence of 

 abundant sectors and the position of the nodus. Megaloprepus 

 shows a more generalized condition than the remaining genera in 

 the short quadrangle, the broad area back of Cu2 with many at- 

 tached sectors, and in the fact that the stigma while diffuse is not 

 so much so as in the others. 



Within the group the same tendencies of specialization appear 

 as in other groups: loss of sectors, narrowing of the wing, reduction 

 in number of cross-veins, straightening of veins, elongation of the 

 quadrangle, and petiolation of the wing. Next to Megaloprepus 

 comes Microstigma (fig. 47), with the quadrangle about five times as 

 long as wide and with M1+2 forking more than half the distance 

 from the subnodus to the tip of the wing. In these respects these 

 two genera differ from Anomisma (fig. 48), but agree with it in hav- 

 ing many secondary sectors and with Cu2 bearing many branches. 

 Anomisma is peculiar in being a genus of Coenagrionidae having a 

 crossed quadrangle, Pseiidostigma (fig. 49) and Mecistogaster (fig. 



