353 



LEPIDOPTERA 



CHAP. 



is certainly a butterfly ; but as the metamorphoses are unknown, 

 we cannot yet form a final opinion as to this curious form. The 

 extraordinary Peruvian Insect, Styx inf emails, is also placed in 

 this family by Staudinger ; it is a small, pale Insect, almost white, 

 and with imperfect scales ; a little recalling a Satyrid. It appears 

 to be synthetic to Pieridae and Erycinidae. 



The caterpillars of Pieridae are perhaps the least remarkable 

 or attractive of all butterfly-caterpillars ; their skins are as a 



rule bare, or covered only with fine, short 

 down or hair ; their prevalent colour is 

 green, more "or less speckled with black 

 and yellow, and they are destitute of any 

 prominent peculiarities of external struc- 

 ture. Pupation is accomplished by the 

 larva fixing itself to some solid body by the 

 posterior extremity, with the head upwards 

 (or the position may be horizontal), and then 

 placing a girdle round the middle of the 

 body. The pupa never hangs down freely 

 as it does in Xymphalidae. It has been 

 by experiment that if the 



B 



9 ? 



FIG. ISO. Pupation of the 



Orange - tip butterfly, ascertained 



XucMoe examines. A, ifdl d t} j b fc t j 



Ine completed pupa ; B, 



the larva, with its girdle, tion can nevertheless be accomplished by 



prepared for the change. ft consitlerable propol . t i on o f larvae. Some 



of the pupae are of very peculiar form, as is the case in the 



Orange-tip (Fig. 180, A) and Brimstone butterflies. The Orange- 



tip butterfly passes nine or 



ten months of each year as 



a pupa, which is variable 



in colour ; perhaps to some 



extent in conformity with 



its surroundings. The North 



American E. genutia has a 



similar life-history, but the 



larva leaves its Cruciferous 



food-plant, wanders to an FIG. 181. Newly-hatched larva of Euchloe car- 



A ' ^ If? j n P rofil< : ; * 01 f 



segment more magnified, showing the liquid- 

 bearing setae ; C, one of the setae still more 

 magnified, and without liquid. 



oak tree, and there turns to 



a pupa, resembling in colour 



the bark of the tree. 



It is riot unusual for caterpillars to change their habits and 



