252 NATURAL HISTORY. [cH, XV. 



to effect this object, the insect adopts the same steps 

 as a human mechanic would pursue under similar 

 circumstances. It splits its garment on the two 

 opposite sides, and in the intervals thus formed, skil- 

 fully inserts two pieces of stuff of the necessary 

 width ; it does not at once split its coat from one 

 end to the other : this would cause the parts to se- 

 parate too widely, as well as expose the caterpillar 

 in a state of nakedness to the action of the open 

 air : to avx^id these inconveniences, it splits each 

 side only half the length of the whole garment ; it 

 then proceeds to the other end, which it enlarges in 

 a similar manner. Thus, instead of two whole 



This figure shows the garment split in half the length. 



length openings, filled up by two whole length pieces, 

 four half length openings and pieces are used. A 

 reasonable agent could not follow a more ingenious 

 or more efficient plan. A coat made in this fashion 

 is not the work of a day nor yet of a month ; differ- 

 ent caterpillars labour with different degrees of dili- 

 gence ; and even the same worm, when deprived of 

 its clothing in an advanced stage of its existence, 

 will finish in one week what it had previously taken 

 it perhaps months to execute. 



The garment of this caterpillar is always of the 

 same colour as the stuff from which its raw material 

 has been taken ; if a worm, enveloped in a blue coat, 

 happen to remove to a piece of red cloth, the addi- 

 tions which may be made to the ends of the tube, or 

 the pieces inserted in the sides to widen it, will be 

 of a red colour ; if it happen to travel over cloth 

 of different colours, its garment will exhibit a cor- 

 responding variety of hues. 



These caterpillars live upon the same materials 



