100 HABITS. 



of the hilly parts of New England prefers the 

 cherry birch, and glues a single egg upon the 

 upper surface of the leaf - at its extreme tip. 

 Similar although even more extraordinary is 

 the place chosen by its cousin, the Red-spotted 

 Purple (Basilarchia Astyanax), which selects 

 the extreme tip of the trembling aspen-leaf, 

 which tapers delicately to a very fine point ; in 

 both these cases, the insect usually deposits 

 but one egg on a tree. The Tiger Swallow-tail 

 (Jasoniades Glaucus) [see Fig. 6] shows sim- 

 ilar care with birches ; while the Gray-veined 

 White (Pieris oleracea) [see Fig. 10] and the im- 

 ported cabbage butterfly (Pieris rapae) dot the sur- 

 face of our turnips and cabbages with pyramidal 

 eggs. In all these cases, the caterpillar feeds 

 upon the plant which the parent has selected ; 

 yet she seldom can see, certainly never has been 

 known by the slightest sign to recognize, the 

 young for whose sustenance she is at such pains 

 to provide. This is one of the wonders and per- 

 plexities of instinctive action. Let us take, for 

 example, the Viceroy (Basilarchia Archippus), 

 which during its butterfly life has never tasted, 

 can by no possibility ever taste, of willow or pop- 

 lar ; that it should choose just these trees neces- 

 sary for the food of progeny it is never to see 

 defies our powers of explanation on any hypo- 

 thesis which leaves all to blind forces. 



