1913.] NATURAL SCIENCES OF PHILADELPHIA. 221 



primary importance in the classification of the Zygoptera. Super- 

 numerary antenodals are often weaker than the normal ones, and are 

 frequently incomplete; that is to say, they may appear as short 

 nervures crossing the costal space alone or the subcostal space alone. 



As already remarked, the second antenodal coincides with the 

 arculus in the typical Agrioninse, but in such genera as Agriocnemis, 

 Argiocnemis, Ceratura, and Hemiphlebia, it comes before the level of 

 the arculus, while it lies beyond it in the fossil genera Melanagrion 

 and Phenacolestes. 



In Neurolestes trinervis De Selys, from Kamerun, we get three 

 complete antenodals constantly present, and, according to its de- 

 scriber, the supernumerarj^ nervure is placed between the usual two. 

 Neuragrion mysticum Karsch was described from a single 9 from 

 Ecuador, and here again there is an additional nervure lying between 

 the ordinary ones. But in this case the nervure is confined to the 

 hind-wings and to the subcostal space only. Of Thaumatoneura, 

 from Central America, two species are known, namely, T. inopinata 

 McLach. and T. pellucida Calv. In this genus a fourth, or even a 

 fifth, antejiodal is occasionally added to the more usual number of 

 three, and in some instances the number is reduced to two. The 

 third, fourth, and fifth antenodals, when present, are placed beyond 

 the level of the arculus and are confined to the costal space. Podop- 

 teryx roseonotata De Selys is represented in the British Museum 

 Collection by three specimens, namely, the type cf , obtained in Aru 

 by A. R. Wallace, and a fine pair (cf & 9 ) from Queensland (F. P. 

 Dodd). The Australian examples do not possess more than two 

 antenodals in any of their wings, but the type specimen has a third 

 antenodal in each wing, beyond the level of the arculus, and crossing 

 the costal space only in three wings, and both the costal and subcostal 

 spaces in the remaining wing. Furthermore, in three wings there 

 is a transverse nervure traversing the subcostal space alone before 

 the first regular antenodal. 



Although the South African genus Chlorolestes does not normally 

 possess more than two cross-veins before the nodus, there are two 

 specimens in the British Museum Collection which exhibit a third 

 cross-vein. One of these insects is a cf of C. longicauda Burm., in 

 the right hind-wing of which the additional nervure is placed between 

 the usual two and ceases at the subcosta. The other is a cf of 

 C. fasciata De Selys, and in this case the added nervure, which ceases 

 at the subcosta, lies before the first normal antenodal in the right 

 hind-wing. 



