BY R. J. TILLY AHL). 241 



curvature which brings it into contact with the wing-border 

 between the base and the anal angle. In the hindwing, the 

 anal veins are smaller, and quite inconspicuous; lA and 2A are 

 simple; 3A is short, but sends a small branch to the wing- 

 border above the anal angle. In both wings, lA is connected 

 with ("Uo by a cross- vein close to its origin; in the forewing, in 

 addition, a short cross-vein connects lA with 2 A. 



It seems probable that very satisfactory, constant, specific 

 characters could, in many cases, be obtained from comparative 

 studies of the anal veins in closely allied species. I5ut the 

 differences in the regions of Rs, M', and Cu' are so numerous and 

 striking that they should always be given preference over the 

 differences in the anal region. The following appear to be the 

 venational differences on which sound species of Chrysopa may 

 be based. 



(1) General shape of wing (breadth, acuteness or roundness of 

 apex, etc.). 



(2) Form of the costa and costal area, especially in forewing, 

 where the costa is often arched upwards, as seen in C. sirpiata. 

 Number of costal cross- veins. 



(3) Presence or absence of pterostigma; if present, its extent 

 and density; also the number and position of the hypostiymatic 

 cross-veins between Sc and R. 



(4) Number of free sectors {e.g., Sj to Sg in C. signata) and of 

 fused or Banksian sectors (e.g., B, to B4 in C. signata) given oft' 

 bv Rs. Dependent upon this would be also the number of cells 

 between 11 and Rs, and the number of upper Banksian cells (6). 



(5) Number of gradate veins in both inner and outer series. 



(6) Form of the median "loop and arculus; position of distal 

 end of ml upon M', in relation with the foot of the cross-vein 

 depending from Rs. 



(7) Number of closed cells beyond arculus, in space between 

 M' and Cu' in forewing; number of same beyond mf in hindwing. 



(8) Number of distal forks (rf/'); number of simple posterior 

 cells ip) before the first (most proximalj distal forl<. 



(9) Differences in the comparative lengths and widths of the 

 three median cells {m^, m^, Wg) in the forewing. Amount of 

 separation of im^ from ini._,. 



