260 PI BRIDGE. 



arched, apex rounded, termen slightly arched, tornus obtuse but 

 well-marked, dorsum slightly convex ; cell not half length of 

 wing ; lower discocellular oblique, concave ; veins 5 and 6 approxi- 

 mate at base, vein 7 emitted from apical half of subcostal ; pre- 

 costal vein inclined outwards. Antennae 

 short, not half the length of the fore wing, 

 club well-marked, spatulate ; head tufted 

 anteriorly ; palpi porrect, third joint slender, 

 acute at apex ; eyes naked : body moderately 

 robust. The males of certain of the forms 

 in this genus bear patches of specialized 

 scales or androconia, which occur either on 

 the upperside of the hind wing as in the 

 typical form, or as in fausta and its nearest 

 Fig. 68. allies on the underside of the fore and upper- 



Colotis, venation. side of the hind wing. 



The forms arranged under this genus, with 



the exception, perhaps, of those that belong to the " hecabe " 

 group of the genus Terias, are of all Pieridce the most variable. 

 Sensitive, as a large majority of the Lepidoptera are when in the 

 pupal state, to slight changes of temperature, moisture, and 

 dryness, the pupae of the above-mentioned genera seem pre- 

 eminently so. A slight difference in the rainfall from one week 

 to another, probably even from day to day, in localities where 

 they are found, seems to affect the shade of the ground-colour, 

 the width and prominence or otherwise of the markings on their 

 wings. In the absence, therefore, of careful breeding-experiments, 

 and even of any long series of carefully localized and dated 

 specimens, any conclusions as to the specific distinctness of the 

 forms must necessarily be more or less tentative. No two 

 authorities agree as to the number of distinct forms of Colotis 

 that occur, even in a limited fauna such as is dealt with in the 

 present series of handbooks. After a long and careful examination 

 of the tolerably large mass of material contained in the collec- 

 tion of the British Museum, supplemented by those in a few large 

 private collections, I have, I find, independently arrived at much 

 the same conclusions as those set forth in the MSS. left by the 

 late Mr. de Nideville. I have not, however, adopted his division 

 of Colotis into subgenera, as the structural differences between 

 certain of the forms do not seem to me sufficient to warrant such 

 subdivision. 



Key to the forms of Colotis. 



A. Upperside: ground-colour on fore and hind 



wings salmon-pink. $ dimorphic. 

 a. Upperside : ground-colour salmon-pink ; in 

 $ sometimes white. Terminal black band 

 on hind wing narrow with a more or less 

 obsolescent series of spots of .he same tint 

 as the ground-colour of the wing, so 

 arranged as to break up the inner edge of 

 the band C. amata, p. 261. 



