23 [June, 



Observations on t7ie last moult of the larva of Stauropus fagi. — Though the 

 earlier moults of this curious larva have been described as occurring with com- 

 parative ease, and observed to occupy no more time than from ten to fifteen minutes, 

 or at most half an hour for the penultimate moult, there yet remains the last moult 

 for me to offer some account of, which happens at night, and is altogether a much 

 more protracted and exhausting operation. 



Specially for this purpose the Kev. Bernard Smith, of Marlow, kindly provided 

 me in the seasons of 1876 — 77 with several examples of the larva, feeding on beech, 

 but with each of them in turn I unluckily failed to witness the last moult, from my 

 inability to continue on the watch sufficiently late at night. 



However, thanks to another generous friend, the season of 1879 brought a further 

 opportunity with a larva of fagi, feeding, this time, on oak, vei*y kindly presented to 

 me by Mrs. Hutchinson, of Leominster, and this was destined to compensate for my 

 previous mischances, as eventually I was able to see the whole of the last moult, to 

 my great satisfaction, and bring the larva to maturity. 



It was on the 3rd of September when I happened to notice the larva had fixed 

 itself midway between the leaves on an oak twig, in preparation for its last change of 

 skin ; whereupon I placed the twig standing erect in a short bottle having a very 

 small neck, and then, by cutting away the lower leaves from the twig, secured an 

 unobstructed view of the larva, which had probably been so fixed thereon all the 

 previous day, as it already had a double headed appearance, from the real head being 

 mostly within the skin of the second segment ; it was grasping the twig with the 

 four pairs of ventral legs and all the front segments were stretched arching backwards 

 over the erected broad segments of the tail, thus forming a more or less circular 

 position. 



Occasionally, though at long intervals, the fore parts of the body would be gently 

 raised up and down a little, sometimes varied with a kind of convulsive heave, and 

 once, after many hours' stillness, the anterior legs were extended laterally to their 

 utmost stretch, quite rigid for a couple of minutes and were then gradually refolded ; 

 quite late at night the tail segments hung down a little but soon were erected again. 



Next morning and throughout the day the first pair of ventral legs and the 

 second pair partly, sometimes wholly, were withdrawn from the twig, the hold of 

 the larva being sustained then by the third and fourth pairs which brought the head 

 down lower than before on one side or the other of the tail ; as night drew on all 

 the anterior legs were outspread to their utmost. 



In early morn of September 5th, I beheld it in the same posture as in the pre- 

 vious night, though about noon the head was even still lower, and with the fore part 

 of the body turned away a little on one side from the tail, and in course of the 

 afternoon suddenly changed over to the opposite side ; thus, with slight variation of 

 detail, for the remainder of the day and evening continued the wonderful exhibition 

 of muscular power and endurance. 



At 10.35 p.m., the larva seemed getting restless and continued to swing itself 

 partly round on the twig, still in the same circular posture, and in a minute or two 

 swung back again, and then commenced, gently at first, writhing backwards and 

 downwards, soon with increasing energy ; the anterior legs having lately been folded 

 together now began to alternately relax outwards and contract again inwards close to 

 the body, in what soon became a regular recurring rhythmic movement in unison with - 



