168 



absent, middle oblique, lower concave or even, slightly angulated 

 inwards ; vein 6 from apex of basal third of: 7, 8 absent, 9 rudi- 

 mentary, a minute branch almost disappearing near apex of wing, 

 10 and 11 free, both from upper third of subcostal. Hind wiug : 

 subtriangular, the costa very long, both apex and tornus evenly 

 rounded, the termen short, gently arched ; cell more than half 

 length of wing, acutely pointed at lower apex, lower discocellular 

 the longest ; precostal vein curved outwards, short. Antennae 

 about half length of fore wing or a little less, club well-formed but 

 gradual ; palpi porrect, slender, third joint short. 



I have taken the genus Pieris in a wide sense as including forms 

 placed by many authors under Mancipium, Pontia, etc. The forms 

 separated off from Pieris, such as brassicce under Mancipium, 

 daplidice, etc. under Pontia, show, so far as the movement of the 

 veins in the fore wing are concerned, degrees of specialization. In 

 the genus Pieris, as in the family Pieridce already noted above, 

 the veins of the median and costal systems in the fore wing show 

 a tendency to shift upwards and outwards towards the apex of the 

 wing and so to disappear. The exact position of any such vein is, 

 therefore, not always constant in the forms of any genus, nor 

 often, indeed, in individuals belonging to the same form. 



Key to the forms of Pieris. 



A. Underside kind wing : markings not green. 

 a. Upperside fore wing : no preapical tri- 

 angular black patch on costa. 

 a'. Underside: A'eius of wings not defined 



with black. 



a 2 . Upperside fore wing: apical black 

 patch not extended along termen 



below vein 4 , P. rupee, p. 169. 



6 2 . Upperside fore wing : apical black 

 patch extended along termen to 

 below vein 3. 



a 3 . Upperside fore wing : inner margin 



of black apical area evenly curved. 



a 4 . Underside hind wing : irrorated 



with black scales P. brassicee, p. 170. 



b'\ Underside hind wing : not irro- 

 rated with black scales, uniform 



ochraceous yellow P. nayanum, p. 171. 



b 3 . Upperside fore wing : inner margin 

 of black apical area not evenly 

 curved, sinuous or scalloped. 

 *. Upperside liind wing : with a 

 continuous terminal black band ; 

 in 9 only traversed very nar- 

 rowly by* the white veins .... P. deota, p. 171. 

 b*. Upperside hind wing : without a 

 continuous terminal black band, 

 only a series of well-divided 

 black spots often mere specks . P. canidia, p. 172. 



