B\' R. J. TILL YARD. 083 



(9) In the forewing, the distal end of 2 A lies alongside 1A; 

 the anal Y-vein formed around them is very prominent in the 

 pupal wing, but is reduced to a very small size in the imago. 



(10) In the hindwing, trachea 1A appears to have been com- 

 pletely eliminated, as in Doratifera. Thus there is no basal Y- 

 vein, and the two aual veins present in the imaginai wing are 

 2A and 3 A, not 1A and 2 A as has hitherto been believed. (See 

 Section v . ) 



At metamorphosis, the changes that take place are much the 

 same as those already described for Wingia, except that there 

 is a much greater comparative increase in the size of the wings. 

 The basal part does not increase at all in size; and, conse- 

 quently, the bases of the tracheae together with the vein M 5 aud 

 the anal loop, become crowded together close to the base, and 

 are hard to make out in the imago. The shape of the fore- 

 wing alters greatly, the base becoming very narrow, by reduction 

 of the anal area, while the distal margin expands, giving the 

 whole wing a triangular shape. In the imago, only the barest 

 remnant of the anal loop can be seen, while 3A is entirely lost in 

 the forewing. The hindwing broadens out on the whole, but its 

 anal area becomes narrowed, instead of widened as in Wingia; 

 3 A is only weakly chitinised. 



Trachea 1 M and Cu are so close in the wings of this insect 

 at metamorphosis, that the transfer of Ciij to M, via M 5 , takes 

 place without any appreciable change in direction; and the 

 serial vein which has M 5 for its basal piece, and Cu x as its 

 distal continuation, is practically a straight line. Moreover, 

 although trachea Cu partly shrivels up, as in Wingia, it appears 

 to become actually enclosed within the thick chitinisation that 

 forms the base of this serial vein. For, in a carefully pre- 

 pared cleared forewing of Euschemon, taken from a specimen 

 that had emerged only four hours previously, I could plainly see 

 the remains of Cu, with its forking into Cuj and Cu 2 , lying just 

 below M 5 within this vein. On the other hand, Cu 2 loses its 

 trachea entirely, and is not chitinised in either fore or hind 

 wing. 



The completion of the basal cell at metamorphosis is a pro- 

 cess of great interest in this insect. If we look at Text-fig. 99, 

 a, we shall see that the narrow eell bounded posteriorly by R 4+5 , 

 anteriorly partly by the main stem of R, and partly by R 2+ 3, 

 and closed distally by the short cross-vein ir between R 3 and 



