358 



LEPIDOPTERA 



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 infernalis, 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 Nymphalidae. It has been 



FIG. 180. Pupation of the 



Orange-tip butterfly, ascertained by experiment that if the 



Euchloe cvrdamims. A, dl d tfl } b fc tfa 



Ine completed pupa ; B, c 



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

 prepared for the change. a consi derable proportion of larvae. Some 



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



Orange-tip (Fig. 1 80, 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. 1 81. Newly-hatched larva of Enchloe car- 

 oak tree, and there turns to damina. A, The larva in profile ; B, one 



segment more magnified, showing the liqmd- 

 a pupa, resembling in colour bearing setae ; C, one of the setae still more 



the bark of the tree. magnified, and without liquid. 



It is not unusual for caterpillars to change their habits and 



