BY R. J. TILLYARD. 231 



hereabouts is supported underneath liy a small vein placed 

 concavely to it, arisinfi; from the cross-vein, and curvinj^- up 

 to join tlie media itself at or near the foot of the first 

 cross-vein descendin*;- from the radial sector (Rs). This small 

 concave vein has been termed the divisori/ vpiuJet (dv) by Banks, 

 as it is supposed to divide the complete "third cubital cell'^c//,) 

 into two unequal parts. The exact shape and position of this 

 divisory veinlet have been used by Banks with considerable 

 success in diagnosing the diftei'ences between numerous closelj" 

 related species. The two undivided cells lying between M and 

 Cu proximad to the "kink" are teraied by Banks the first and 

 aecond ciibital celh respectively {cii-^, cuo). As it is usual, in the 

 Comstock-Needham terminolog)^, to name the basal spaces after 

 the main veiias bounding them above, and not below, it would 

 have been moi-e consistent to have termed these thi'ee cells the 

 "median cells," reserving the term "cubital cells" for those in 

 the row below them. 



The gradate reins {y, y') are very constant in position in the 

 Chrysopidce, forming two series of cross- veins rising, as it were, in 

 a series of steps from the media upwards through the parallel 

 branches of the radial sector. Often, as in the species under 

 discussion, the inner series of gradate veins {y) is one less in 

 number than the outer series ((/'); sometimes the inner series is 

 much reduced in number. 



The form of the pterostiyma {pf) varies greatly in the different 

 species, and is never of more than specific value. In C. slynata, 

 there is a distinct greenish pterostigma on both wings. That of 

 the forewing is confined between C and Sc, and svipported 

 beneath by six cross-veins between Sc and R. In the hindwing 

 it is denser, and is continued into the space between Sc and R. 

 The cross-veins in this space are, however, present, though not 

 easy to see. 



The result of a study of the pupal wing-tracheation (Text-fig. 

 5) shows us that the accepted interpretation of the imaginal 

 venation is quite incorrect as regards the media and cubitus of 

 both wings, and also as regards the origin of the radial sector in 



