CLOTHES MOTHS AND OTHER TINE^ 95 



To lengthen the case all that is necessary is to add 

 successive rings of silk and woollen fibres to the ends ; 

 but even in this simple operation there is a choice of 

 methods, for the addition might be made at one end 

 only or at both. The latter device is the one adopted. 

 First of all a ring of new material is added at one end, 

 to effect which the grub does not need to leave its tunic, 

 the whole operation being able to be performed from the 

 inside ; a layer of silk is spun out in the form of a con- 

 tinuous thread, and then a number of tiny fillets of the 

 woollen fabric, or fur, are attached to its outer surface 

 by other silken threads. This done, the caterpillar, still 

 without quitting its shelter, rapidly reverses its position, 

 bringing its head into the position previously occupied 

 by its tail. The extreme flexibility of its body, and the 

 rather wider diameter of the case in the centre, enable 

 it to do this very quickly ; then the same addition of a 

 ring of felt is carried out at the tail end, and in this way 

 the case is elongated equally at the two ends, and what 

 was originally the middle always remains such, and 

 therefore the oldest part is always to be found in the 

 centre, and the newest at the ends. 



When the grub is full fed, it must set its house in 

 order and prepare for the helpless condition which pre- 

 cedes its final metamorphosis. The chrysalis state is 

 assumed inside the case, the caterpillar becoming, by 

 throwing off its last larval skin, a little yellowish-brown 

 helpless thing, similar in form to the well-known 

 chrysalis of the larger moths. Now a danger has to be 

 guarded against : the insect has to remain some weeks 

 in this state of inactivity, and if the case with its 

 precious freight were simply left lying on the cloth as 

 usual, any moving of the latter might cause the little 

 bundle to roll off and fall, no one knows whither, and 



