444 MOTIONS OF INSECTS. 
of this kind, moving differently in its preparatory states, is entitled to notice 
under the present head. In a late letter, I mentioned to you a bug 
een personatus), which usually covers itself with a mask of dust, and 
ragments of yarious kinds, cutting a very grotesque figure. Its awkward 
motions add not a little to the effect of its appearance. When so disposed, 
it can move as well and as fast as its congeners ; yet this does not usually 
answer its purpose, which is to assume the appearance of an inanimate sub- 
stance. It therefore hitches along in the most leisurely manner possible, 
as if it was counting its steps. Having set one foot forwards (for it moves 
only one leg at a time), it stops a little before it brings up its fellow, and 
so on with the second and third legs. It moves its antenna in a similar 
way, striking, as it were, first with one, and then, after an interval of 
repose, with the other.1_ The pupz of gnats also, as well as those of many 
other aquatic Diptera, retain their locomotive powers ; not, however, the 
free motion of their limbs. When not engaged in action, they ascend to 
the surface by the natural levity of their bodies, and are there suspended 
by two auriform respiratory organs in the anterior part of the trunk, their 
abdomen being then folded under the breast; when disposed to descend 
the animal unfolds it, and by sudden strokes which she gives with it and 
her anal swimmers to the water, she swims to the right and left as well as 
downwards, with as much ease as the larva.? 
Bonnet mentions a pupa which climbs up and down in its cocoon, —and 
that of the common glow-worm (Lampyris noctiluca) will sometimes push 
itself along by the alternate extension and contraction of the segments of 
its body.* Others turn round when disturbed. That of a weevil (Hypera 
arator), which spins itself a beautiful cocoon like fine gauze, and which it 
fixes to the stalks of the common spurrey (Sagina arvensis), upon my 
touching this stalk, whirled round several times with astonishing rapidity. 
The chrysalis of a moth (Hypogymna dispar) when touched turns round 
with great quickness; but, as if fearful of breaking the thread by which it 
is suspended by constantly twisting it in one direction, it performs its gy- 
rations alternately from left to right and from right to left.4 Generally 
speaking, quiescent pupz when disturbed show that they have life, by 
giving their abdomen violent contortions, 
But the most extraordinary motion of pupz is jumping. In the year 
1810 I received an account from a very intelligent young lady, who collected 
and studied insects with more than common ardour and ability, that a friend 
had brought her a chrysalis endued with this faculty. It was scarcely a 
quarter of an inch in length; of an oval form; its colour was a seml- 
transparent brown, with a white opake band round the middle. It was 
found attached, by one end, to the leaf of a bramble. It repeatedly jumped 
out of an open pill-box that was an inch in height. When put into a 
drawer in which some other insects were impaled, it skipped from side to 
side, passing over their backs for nearly a quarter of an hour with surprising 
agility. Its mode of springing seemed to be by balancing itself upon one 
extremity ofits case. About the end of October one end of the case grew 
black, and from that time the motion ceased; and about the middle o 
April, in the following year, a very minute ichneumon made its appearance 
by a hole it had made at the opposite end. Some time after I received 
1 De Geer, iii. 284, 2 Thid. vi. 808. 
5 Ibid. iv, 48. 4 Dumeril, Trait, Bement. ii, 49, n. 603. 
