242 M. Huber on the Habits of a Saiv-fly. 



of a hand for holding the leaf upon which the insect is feed- 

 ing or working. The length of this larva varies from six to 

 eight lines, it is half a line thick ; its ordinary colour is bluish 

 green, the head is yellowish, and the feet are black; there 

 is a small black spot on the first ring. In its first stage this 

 insect lives upon the hazel-tree. 



Most larvae of Tinea and other insects expert in forming for 

 themselves cases (fourreaux) carry them about with them, but 

 (during the early period of its life at least) the larva in question 

 is obliged to leave its case fixed to the leaf out of which it has 

 been formed ; it therefore preserves all the verdure of the 

 leaf itself ; at last, however, comes the time when this larva 

 separates the case from the leaf and carries it from place to 

 place. The case in which it envelopes itself is of a very sin- 

 gular form ; it is a very much lengthened hollow cone, very 

 narrow at the end with a rather wide mouth ; it is made of a 

 strip or band of a hazel-leaf rolled in a spiral form and com- 

 posed of a number of variable whorls ; this strip, very nar- 

 row at the lower extremity, at first produces only very nar- 

 row whorls and of small diameter, for at first the larva wants 

 but a very narrow case. When complete it is from twelve to 

 fourteen lines in length, and two lines in diameter at its ori- 

 fice ; it is composed of more than ten turns, the exterior part 

 of the case presenting the upper surface of the leaf, the ser- 

 rated edge of which is preserved entire, turned towards the 

 point of the cone. This dwelling is very spacious for our larva, 

 and it can turn itself about in it with the greatest ease. 



It forms this cone by cutting along the edge of the leaf a 

 narrow strip, which it then winds spirally around itself by a 

 method which I shall presently describe. When this portion 

 has taken the desired form or position, it goes on cutting the 

 band a little further up, and always nearly parallel with the 

 edge of the leaf. By little and little it rolls around itself a 

 fresh portion, and so on during all the time of its growth ; so 

 that the cone, which was at first very short, lengthens every 

 time that the larva works at it. But it is not content with 

 clothing itself; it feeds as it goes on, it even eats prodigiously ; 

 only, while eating, it takes good care to attend to the arrange- 

 ment of the strip or band necessary for its clothing ; it eats 

 according to method, and with the double object of providing 

 itself at once with board and lodging ; I say lodging, for this 

 case, being too roomy to be justly considered as a mere gar- 

 ment, serves it rather as an asylum than as a defence against 

 the inclemency of the weather. 



Another part of the skill of this insect consists in knowing 

 how to roll this bandage round itself, which unsupported would 



