S2 



PSYCHE. 



[July— August iSSS. 



small pea), farther and fartlier down the 

 midrib away from its perch, always 

 keeping it near the eaten edge. It should 

 1)6 noted that it is so loosely attached, 

 the bits of leaf at all possiljle angles, 

 that it is moved by the least breath. 

 Meanwhile the caterpillar has been 

 growing larger and more conspicuous 

 and thus in greater peril from its ene- 

 mies. There are two possible services 

 that this odd packet may render. A 

 spider wandering over the leaf and ob- 

 serving its motion may seize it and think- 

 ing it has a prize hurry away with it 

 and leave its architect unharmed. This 

 seems to me rather a strained sugges- 

 tion, for a wandering spider would 

 probablv proceed to investigate it on 

 the spot. Another explanation seems 

 more probable. It should be remem- 

 bered that the leaves preferred by tliese 

 creatures as food are mostly such as are 

 easily shaken by the wind, and as the 

 caterpillar moves with the leaf and with 

 all the surrounding leaves, in a contin. 

 ual fluttering in the case of the trembling- 

 aspen, and to a less degree in the other 

 food-plants, this of itself is a protection 

 to it, as it would more readily escape 

 observation as an object distinct from 

 the leaves, all being in motion together ; 

 but on the more stable leaves like the 

 willow and especially the Rosaceae and 

 the oaks, the motion in a feeble wind 

 would not be sufficient to be serviceable, 

 and here at least the packet comes into 

 play. An object in motion among 

 others at rest is a most noticeable thing, 

 a fact well recognized among animals, 

 as a host of them show when they fear 



being seen. This packet attached by 

 loose silken threads moves, as stated, 

 with a l)reath of wind and so would dis- 

 tract attention from its architect near by, 

 who has taken pains to place it at the 

 farthest remove from its perch, while 

 still (to avoid undesirable steps) on its 

 daily track. If this be really its object, 

 it is surely one of the oddest devices in 

 nature. 



The species of Basilarchia all pass 

 the winter while in the caterpillar state 

 and but partly grown. The caterpillar 

 has moulted at least once (devouring 

 its cast-oft' clothing, by the way, doubt- 

 less that it may not attract attention) 

 and has to prepare against the incle- 

 ment season. This it does in a very 

 shrewd way, which is all the more re- 

 markable because no trace or semblance 

 of it is seen in caterpillars of the broods 

 that attain their entire growth in the 

 same season. When the proper time 

 approaches, warned thereto possibly by 

 the dryness of its food, or by the cooler 

 nights, the caterpillar constructs a little 

 nest, sometimes from the still unfinished 

 leaf on which it was born, sometimes 

 from one which it prepares specially at 

 greater pains ; this is done by eating 

 awav or biting oft'the unnecessary parts, 

 and leaving on either side of the base of 

 the leaf little flaps just large enough, 

 when drawn together, bottom side up 

 and meeting above, to form a cylinder 

 into which it can squeeze ; a project- 

 ing shelf is also left beyond the open- 

 ing, on which it may stand when ready 

 to crawl in, and upon which it may 

 back out in the spring; the whole 



