Dr. M. Burr — Notes on the ForficuUiria. 79 



Behind the squama is a clear, almost veinless, field, the 

 ulnar area, bounded anteriorly by the posterior margin of 

 the squama, and elsewhere by the strongly curved and pro- 

 minent ulnar vein. 



The whole of the rest of the wing is delicate and mem- 

 branous ; this is the prominent anal area. 



From the apex of the ulnar area there radiate seven 

 ncrvures, which extend to tlie margin of the wing. These 

 radial ncrvures are altogether twelve in number, the re- 

 mainder arising from the more l)asal portion of the ulnar 

 vein. Intercalated within these ncrvures there are in all 

 nine secondary nervures, which arise midway between the 

 ulnar vein and the margin : all these are connected by a 

 spurious vein which runs a short distance inside the pos- 

 terior margin of the wing, and parallel to it, from the base 

 to the apex. A little distance inside this spurious vein, each 

 nervure, both main and secondary, is slightly dislocated by 

 what may be described as an incipient secondary spurious 

 vein. About this point each secondary nervure is usually 

 somewhat chitinised and inflated. The nervures are nearly 

 all bent at this point. 



In the squama there are, according to Zacher, always 

 three chitinised veins which he provisionally discriminates 

 by numbers^ the first and third forming the anterior and 

 posterior boundaries of the squama, the third being short, 

 only extending about a quarter of the total length of the 

 squama, and straight. In some instances these are con- 

 nected near the basal portion by a cross-vein. The third 

 vein sometimes has a sector branching from it into the 

 ulnar area. 



In the apical portion of the latter, an inner branch arises 

 and is directed towards the base, to meet the apex of the 

 sector. As a rule, these two fail to meet, the ends of each 

 being obsolete, but in some instances their junction can be 

 detected under a high power. 



The apical area usually has a faint longitudinal vein. 



The first eight radial nervures, continuing from the apex 

 backwards towards the axillary angle, are more or less 

 straight : sometimes the ninth, always the tenth, eleventh, 

 and twelfth, are of irregular shape. 



"When the wing is folded, it shuts like a fan radially about 

 the starting-point of the nervures, arising at the apex of the 

 ulnar area; and then again is folded in a plane at right 

 angles, about the line or hinge which separates the apical 

 area from the squama. 



