30 THE STRUGGLE FOR EXISTENCE 



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 breath of wind and so would distract atten- 

 tion from its architect near by, who has taken pains 

 to place it at the farthest remove from his perch, 

 while still (to avoid undesirable steps) on his 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 (devour- 

 ing its cast-off clothing, by the way, doubtless that 

 it may not attract attention) and has to prepare 

 ao'ainst the inclement season. This it does in a 

 very shrewd way, which is all the more remark- 

 able 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 wliich it prepares specially at 



