of apparent 

 ttbstitittion of a SEing for a feg in a Jftoth 



(Zygcena filipendulce.) 



By N. M. RICHARDSON, B.A. 



the summer of 1877 I collected from a chalk-pit 

 near Cambridge about 700 pupae of Zygcena 

 filipendulce, in order to breed the yellow variety of 

 that species which occurred there. I bred a few 

 (5 or 6 as far as I can remember) yellow ones, and 

 also one specimen with 5 wings and only 5 legs : 

 the left hind-leg is absent, its place being occupied by a fifth wing. 

 This specimen is a male of the ordinary red colour, of medium size 

 (1" 3J'" in expanse of wings), with the ordinary markings, and 

 perfectly developed ; in fact, there is nothing at all unusual about 

 it except the extraordinary peculiarity above mentioned. The 

 extra wing resembles an ordinary hind-wing of this species in 

 shape and appearance, but is much smaller. It is 3'" in length and 

 2'" in breadth, whereas the hind-wing of this specimen is 4|"' long 

 by 2J'" broad. The extra wing is much more thinly clothed with 

 scales than the others, being most covered near the base. On the 

 posterior margin of the basal half there is a distinct blackish 

 border corresponding to that on the hind-wing. There is also a 

 slight blackish border on the basal half of the under side of the 



