250 



MOTIONS OF INSECTS. 



members that are put in motion. They will not, or rather 

 cannot, stir a step till their antennae are removed from their 

 station of repose and set in action. When the chafers or pe- 

 talocerous beetles are about to move, these organs, before 

 concealed, instantly appear, and the laminae which terminate 

 them being separated from each other as widely as possible, 

 they begin their inarch. They employ their antennae, how- 

 ever, not as feelers to explore surrounding objects, — their 

 palpi being rather used for that purpose, — but, it should 

 seem, merely to receive vibrations, or impressions from the 

 atmosphere, to which these laminae, especially in the male 

 cock-chafers, or rather tree-chafers (Melolonthce), present a 

 considerable surface. Yet insects that have filiform or seta- 

 ceous antennae appear often to use them for exploring. When 

 the turnip-flea (Haltica oleracea) walks, its antennae are alter- 

 nately elevated and depressed. The same thing takes place 

 with some woodlice (Oniscidce), which use them as tactors, 

 touching the surface on each side with them, as they go along*. 

 This is not however constantly the use of this kind of an- 

 tennae ; for I have observed that Telephones lividus, — a nar- 

 row beetle with soft elytra, common in flowers, — when it 

 walks vibrates its setaceous antennae very briskly, but does 

 not explore the surface with them. The parasitic tribes of 

 Hymenoptera, especially the minute ones, when they move, 

 vibrate these organs most intensely, and probably by them 

 discover the insect to which the law of their nature ordains 

 that they should commit their eggs ; some even using them 

 to explore the deep holes in which a grub, the appropriate 

 food of their larva, lurks. 1 But upon this subject I shall have 

 occasion to enlarge when I treat of the senses of insects. 

 Antennae are sometimes used as legs. A gnat-like kind of 

 bug {Ploiaria vagabunda) has very short anterior legs, or rather 

 arms ; while the two posterior pair are very long. Its an- 

 tennae also are long. When it walks, which it does very 

 slowly, with a solemn measured step, its fore-legs, which per- 

 haps are useful only in climbing, or to seize its prey, are 

 applied to the body, and the antennae being bent, their ex- 



1 Marsham in Linn, Trans, iii. 26. 



