308 MOTIONS OF INSECTS. 



the chafers or petalocerous 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 march. 

 They employ their antennae, however, 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 Iamina3, especially in the male cock- 

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

 considerable surface. Yet insects that have filiform or 

 setaceous antennae appear often to use them for explo- 

 ring. When the turnip-flea (Haltica oleracea) walks, its 

 antennae are alternately elevated and depressed. The 

 same thing takes place with some woodlice (Oniscida), 

 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 antennae; for I have 

 observed that Telephorus lividus^ a narrow 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 Hyme- 

 noptera, especially the minute ones, when they move vi- 

 brate these organs most intensely, and probably by them 

 discover the insect to which the law of their nature or- 

 dains 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 a . 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 (Ploiera vagabunda) 

 a Marsham in Linn. Trans, iii. 26 . 



