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 I'ieridae 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 

 ascertained by experiment that if the 

 girdle round the larva be cut, the pupa- 

 tion can nevertheless be accomplished by 

 a considerable proportion of 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 .EmcAZoc car- 

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

 . segment more magnifteil, showing the liquid- 

 a pupa, resembling m 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 



Fio. ISO. — Pupation of the 

 Orange-tip luitterfl.v, 

 Evddoe cardamines. A, 

 The completed pupa ; B, 

 the larva, with its girdle, 

 prepared for the change. 



