M. Huber on the Habits of a Saw-fly. 245 



in succession. Our traveller at last arrives at the end of its 

 journey, that is to say, at the end of the leaf It then brings 

 its case near its under surface, and adjusts it or places it in 

 such a way as to be situated in the plane of the leaf; but on 

 the outside he sets it up as sailors raise a mast on its base, 

 only so as to be placed horizontally in the air, and that instead 

 of drawing the cords on the side where it Avishes to make it fast, 

 it finds the means of establishing shorter and shorter threads 

 of silk, and bursts the old threads that kept it in a vertical 

 position. It has, in short, the art to lead the spiral tube to the 

 suitable place and into the position requisite for again begin- 

 ning its rolling up. It cuts off the inequalities and adjusts it 

 so neatly to the edge of the leaf, which is also prepared before- 

 hand for this purpose, that the junction of the two pieces 

 shall be imperceptible. The leaf tits exactly at the edge of the 

 case ; threads of silk, carefully stretched within, sew together 

 (if we may so speak) the two parts, and the caterpillar then 

 setting itself to gnaw the leaf, eats it parallel to its edge, so 

 as to give it the dimensions of the bandage of the case. 



I shall conclude this notice with the last experiment that I 

 made on one of these larvae, and the result of which presents 

 some very curious particulars. It was still young, it had com- 

 posed its case of twelve whorls, and I saw that it had added 

 one or two turns of new ribbon. It was working at it when 

 I took it out in order to lay it bare ; I then perceived that the 

 portion of the case newly added being looser than it ought, 

 and consequently the AAhorl being too wide at this part, the 

 insect had obviated this inconvenience by spinning around 

 itself such a number of threads that they formed a narrow 

 sheath at the orifice of the case. 



The larva being exposed, was gently laid upon a fresh and 

 tender hazel-leaf, the underside of the leaf being turned up- 

 wards. At first it appeared embarrassed ; it tried to turn upon 

 its back, and it was only after many trials and efforts that it 

 succeeded in effecting this ; from this time it regained courage, 

 and sought to carry its head from right to left of its body in 

 order to reach the leaf in this position ; but the want of a point 

 d'appui for a long time hindered it from accomplishing this. 

 However, by dint of twisting itself about, it at last succeeded, 

 placing its spinneret upon the leaf on its right side ; by a cir- 

 cular movement of the head, it led a thread from thence to its 

 left side passing above its body ; from that time it no longer 

 appeared embarrassed ; the movements became quicker and 

 quicker; it had soon made a lace-work of silk above itself, 

 fitting well enough to hold it closely against the leaf, yet 

 without cramping it. By help of these threads it became 



