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and length, does not provide for the increment in 

 the way adopted by the caterpillar of the Clothes 

 Moth. The Caddis Worm's method set down on 

 paper may look suspiciously like that of the legendary 

 Irishman who is said to have lengthened a too 

 short blanket by cutting a piece off the top and 

 sewing it on the bottom. As the Caddis case gets 

 too strait, he cuts a piece off the rear, which is the 

 inconvenient portion, and makes additions to the 

 front end. By always maintaining the slight 

 tapering form in this way, there is never any 

 necessity to split the case down the sides and insert 

 gussets. 



Before the change to the chrysalis stage comes 

 the Caddis Worm prepares for it by stopping up 

 the ends of its case against unfriendly visitors. 

 Care is taken, however, to allow a sufficient gap 

 for water to flow through, for even in the pupa 

 state it requires to breathe. The stopping is 

 variously effected according to species : some using 

 vegetable debris to form a plug, others spinning a 

 grating of silk threads. 



Micropterna, which lives in swift streams, takes 

 precautions against its case being swept down- 

 stream, and perhaps buried, owing to the absence 

 of guiding limbs from its doorway. Its method 

 is to get bigger stones than its case consists of, and 

 to attach these to the front or wider end. It then 

 closes up that end with a silk grating, doubles on 

 itself in the case, and thrusts its head out at the 

 smaller end. It digs a hole in the bed of the 



