60 ENTOMOLOGICAL NEWS [Feb., 'll 



and where they can be seen through it. Even in these ex- 

 ceptions the veins appear fainter and narrower on one sur- 

 face than the other and are stronger and wider on their proper 

 surface, e. g. Sc and Mi, concave veins, on the outer surface; 

 Ri, A and Cu2b, convex veins, on the inner surface. 



Another fact shown by these comparisons and the figures 

 is that the cross-veins only appear continuous from one longi- 

 tudinal vein to another when the two longitudinal veins so 

 connected are two, one of which immediately follows the other 

 in the imaginal wing. (Cf. the cross-veins between Ri and 

 Mi and between Mi and M2 in PI. Ill, fig. 24.) 



It would thus appear that each longitudinal vein develops on 

 one surface of the wing-rudiment before it appears on the 

 other surface. Before transformation is reached each vein 

 has formed on both surfaces of the future wing but not neces- 

 sarily equally on both surfaces, as may be seen from Hagen's 

 figures (1889) from photographs of wings split into their two 

 laminae immediately after transformation and expansion. 



These facts of the development of the veins on one surface 

 of the wing-rudiment before the other have a practical value 

 in identifying Odonate larvae by this method and do not seem 

 to be included in Prof. Needham's (1904, p. 687) suggestions 

 on this point. 



In the larva of Cora there exist the following generalized 

 features : antennae with no hypertrophied joint, biramous man- 

 dibles, paired ventral tracheal gills (if they be morphologically 

 equivalent to legs), and perhaps the empodium-like part, side 

 by side with specialized features in the form of cuticular 

 scales, almost completely fused halves of the labium and thick- 

 ened, shortened caudal gills. If to these generalized parts of 

 the larva we add the generalized features of the imaginal 

 venation pointed out or implied by Prof. Needham (19030, 

 pp. 731, 746), we have good grounds for looking on Cora and 

 its allies as being in many respects the most primitive of living 

 Odonata. 



