ON ENTOMOLOGY. 25 



drop of gluten to the branch, and drawing it out (as a spider does his 

 line) to the requisite length before the egg is deposited upon the sum- 

 mit. As she uses her body for a measure, the footstalks are by conse- 

 quence all nearly of equal length. It is evidently the design of these 

 footstalks to place the eggs out of the reach of the Grubs of Lady Birds 

 (Coccinella), and Aphidivorous Flies (Syrphi), which frequent the same 

 situation and might devour them. The footstalks are so smooth and 

 slender that these Grubs could not climb them, as we have proved b^ 

 experiment. 



A singular structure for respiration occurs in the aquatic larvae of the 

 Dragon Flies, LIBELLULID*:, which differ so remarkably from the perfect 

 insect in the beauty of colour and elegance of form, that has procured 

 for them the gallant appellation of Demoiselles (damsels) in France. This 

 title agrees as badly with their habits as the popular English name of 

 Horse-stingers, since they have no apparatus for stinging ; and so far, 

 says Reaumur, from seeking an innocent nutriment in the pulp of fruit 

 or the nectar of flowers, they are more like amazons than damsels, hover- 

 ing in the air only to pounce on other insects, which they crush with 

 their powerful mandibles. Should they quit the margin of a pond or 

 the banks of a rivulet, where they may be seen hawking about in multi- 

 tudes, it is only to pursue and seize the Moth or the Butterfly that has 

 fled for shelter to the bushes. Though these Larva are furnished with 

 six feet, they not only move very little, but do not use them for walking 

 so much as for capturing their prey. Their motion is effected by a very 

 peculiar method. When one of these Larvcz is procured from the bot- 

 tom of a pond or the pool of a brook, let it be put into a large saucer 

 with water and some of the dead leaves or sticks it previously em- 

 ployed as a covering j these will soon be seen floating towards the tail, 

 and afterwards repelled, as a floating feather will be by a stick of seal- 

 ing-wax or a bit of amber when electrically excited. When the insect 

 has been kept out of the water for a short time, the desire or necessity 

 of respiration is increased, and when again put into the water, the pump- 

 ing is repeated with unusual force and frequency. If it be held in the 

 hand head downwards and some drops of water be let fall on the tail, 

 it instantly sucks it in, and the dimensions of its body become visibly 

 augmented ; but it collapses again when the water is expelled, which is 

 effected by the same apparatus. The Larva of the Libellula has placed 

 on its head a horny consistence in plates resembling a mask, that if 

 Entomologists ever went to masquerades, they could not more effectually 

 relieve the insipidity of such amusements, and attract the attention of 

 the demoiselles, than by appearing at the supper table with a mask of the 

 same construction as the Libellula's, and serving themselves by its as- 

 sistance. It would be difficult to be sure by mechanism to supply the 

 place of the muscles with which this insect is provided, but Merlin, 

 or his successor, has surmounted greater obstacles. When the pupa is 

 about to change to the perfect insect, it may be seen removing out of 



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