240 



MOTIONS OF INSECTS. 



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. 1 



Bonnet mentions a pupa which climbs up and down in its 

 cocoon, — and that of the common glow-worm (Lampyris noc- 

 tiluca) will sometimes push itself along by the alternate ex- 

 tension and contraction of the segments of its body. 2 Others 

 turn round when disturbed. That of a weevil {Hyper a 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. 3 

 Generally speaking, quiescent pupae when disturbed show that 

 they have life, by giving their abdomen violent contortions. 



But the most extraordinary motion of pupse is jumping. 

 In the year 1810 I received an account from a very intel- 

 ligent 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 semitransparent 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 of its case. 

 About the end of October one end of the case grew black, 

 and from that time the motion ceased ; and about the middle 

 of April, in the following year, a very minute ichneumon 

 made its appearance by a hole it had made at the opposite 



i Ibid. vi. 308. 9 Ibid. iv. 43. 



3 Dumeril, Trait. Element, ii. 49. n. 603. 



