The Life of the Caterpillar 



facilitate the action of the head and legs 

 when a new piece Is to be placed In position, 

 the front part of the sheath requires a special 

 structure. Here a casing of beams is no 

 longer allowable, for their length and stiff- 

 ness would hamper the artisan and even make 

 his work Impossible; what is essential here 

 is a flexible neck, able to bend in all direc- 

 tions. The assemblage of stakes does, in 

 fact, end suddenly at some distance from the 

 fore-part and is there replaced by a collar 

 in which the silken woof is merely hardened 

 with very tiny ligneous particles, tending to 

 strengthen the material without impairing its 

 flexibility. This collar, which gives free 

 movement, is so important that all the Psyches 

 make equal use of it, however much the rest 

 of the work may differ. All carry, in front 

 of the faggot of sticks, a yielding neck, soft 

 to the touch, formed inside of a web of pure 

 silk and velveted outside with a fine sawdust 

 which the caterpillar obtains by crushing with 

 his mandibles any sort of dry straw. 



A similar velvet, but lustreless and faded, 

 apparently through age, finishes the sheath at 

 the back, in the form of a rather long, bare 

 appendix, open at the end. 



190 



