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 infernal is, 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 l*ieridae are perhaps the least remarkal)le 

 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 1)y the 

 larva fixing itself to some solid body by the 

 posterior extremity, with the head upwards 

 (or the position may he 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 . "^ ^ . •,. i 



Orange-tip hutterfly, ascertained by experiment that it the 

 £HcMoe ccmimnhies. A, -^.^iig ^,q^^j^^| ^ihe larva be cut, the pupa- 



The completed pupa ; B, » ' r i. 



the larva, witii its girdle, tiou caii nevertheless be accomplished by 

 prepared for the change. ^ considerable 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 Nortli 



American U. genutia has a 



similar life-history, but the 



larva leaves its Cruciferous 



food-plant, wanders to an Fig. 181.— Newly-hatched larva of £?^(;/i?oe c«r- 



oak tree, and there turns to ^«""'"^f- ^' '^^^ ^fl'' !" P"""*^!^ ' f ' •^.^ 



' _ _ segment more magnified, snowing the Jiquid- 



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 



