240 STUDIES IN AUSTRALIAN NEUROPlERA. iii. 



freshly formed pupal wing, but is formed during the subsequent 

 rucking of the wing, which begins on the second or third day of 

 pupal life. In Plate xi., fig. 3, I photographed the hindwing of 

 a pupa of Chryso'pa A, nearly three days old. Here tlie trans- 

 verse rucking is plainly to be seen beginning, and the overlapping 

 is already very considerable. In a pupa four or five days old, the 

 rucks are so great that a photograph is useless. However, the 

 final amount of overlapping is easily determined by working back 

 from Rs at the apex of the wing, and counting the number of 

 distal forks {df). Thus in both wings of C . ^^gnata there ai'e no 

 forks on Sj to 84; Sg and Sg are forked; Bj, Bo, and IJg are simi- 

 larly forked; B4 has a branch as well as a small fork: Mj and 

 M2 each send two veins to the border, and Cuj three. Counting 

 backwards, therefore, these can all be correctly placed. As the 

 positions of Bj to B4 on Rs are known also, it follows that the 

 amount of overlapping of, say, B3 on B4, in order to carry each 

 of tliese veins from its original level on Rs to its final level on 

 the posterior wing-border, must be as shown in the transparency. 

 The result might also have been deduced, with very little doubt, 

 from a study of Plate xi., Hg.3, alone. 



The Forviation of the PterosfAgyna. —This peculiar, thickened, 

 green patch on the wing is not present in all species. Its forma- 

 tion is rather striking. Instead of running along under the 

 pterostigma to form its base, as we might expect, 8c only 

 penetrates a very short way from the pi'oximal end of tlie patch. 

 Beyond that, a series of small tracheas arises from R, and their 

 ends bend over so as to continue roughly the line which we 

 should have expected Sc to follow. This accounts for the pre- 

 sence of the cross-veins between Sc and R in the imaginal vena- 

 tion. It also probably explains why the pterostigma descends to 

 R in the hindwing, since there is no continuous trachea 8c inter- 

 posed between R and the costal margin. 



The Anal Veins. — ^In the pupal tracheation there are three 

 distinct anal veins arising somewhat in a bunch below Cu. In 

 the forewing, lAis branched; likewise 2A, but the proximal 

 branch descends upon 3 A, and appears as a cross-vein in the 

 imaginal venation; 3 A is unbranched, but undergoes a double 



