248 SENSES OF INSECTS. 
Various opinions have been started concerning the use 
of the palpi. Bonsdorf thought that they were organs of 
smell ; Knoch, that this sense was confined to themazillary 
ones, and that the dabzal ones were appropriated to taste? : 
but the most early idea, and that from which they derive 
their present name of palpi (feelers), is, that they are or- 
gans of active touch; and this seems to me the most cor- 
rect and likely opinion. Cuvier, himself a host, has em- 
braced this side of the question”, and Lehmann also ad- 
mits it®.. The following observations tend to confirm 
this opinion. The palpi of numerous insects when they 
walk, are frequently, or rather without intermission, ap- 
plied to the surface on which they are moving—this you 
may easily see by placing one upon your hand; which 
seems to indicate that they are feelers. In the Aranezde 
they are used as legs; and by the males at least, as excz- 
ting if they be not really genital organs4. In the Scor- 
pionide they answer the purpose of hands: besides being 
usually much shorter than antenne, they are better cal- 
culated to assist an insect in threading the dark and tor- 
tuous labyrinths through which it has often to grope 
its way, and where antennee cannot be employed. I 
have noticed that Hydrophili—in which genus the palpi 
are longer than the antennze—when they swim, have their 
antennee folded; while the palpi are stretched out in front, 
as exploring before them. As the palpi are attached to 
the under-jaws and under-lip, we may suppose they are 
@ Lehmann De Sens. Extern. Anim. Exsang. De Olfactu. 
> Cuv. Anat. Comp. ii. 675. © Ubi supr. 
4 Marcel de Serres says they are connected with ¢estes seated in 
the trunk, (dem. du Mus. 1819, 95); but Treviranus denies this 
(Arachnid. 36—. t. iv. f. 33). 
