490 MOTIONS OF INSECTS. 



Climbing is another motion of insects that merits particular considera- 

 tion : since, as lliis includes their power of moving against gravity — as 

 we see flies and spiders do upon our ceilings, and up perpendicular sur- 

 faces even when of glass, it affords room for much interesting and curious 

 inquiry. Climbing insects may be divided into four classes. Those that 

 climb by means of their claws ; those that climb by a soft cushion of 

 dense hairs, that, more or less, lines the underside of the joints of their 

 tarsi, the claw-joint excepted ; those that climb by the aid of suckers, 

 which adhere (a vacuum being produced between ti)em and the plane of 

 position) by the pressure of the atmosphere ; and those that are enabled 

 to climb by means of some substance which they have the power of 

 secreting. 



The first order of climbers — those that climb by means of the'w daws — 

 includes a large proportion of insects, especially in the Coleoptera order — 

 the majority of those that have five joints in iheir tarsi being of this 

 description. The predaceous tribes, particularly the numerous and prowl- 

 ing ground-beetles (^Eutrech'ma,), often thus ascend the plants and trees 

 after their prey. Thus one of them, the beautiful but ferocious Cahsoma 

 sycophanta, mounts the trunks and branches of the oak to commit fearful 

 ravages amongst the hordes of caterpillars that inhabit it.^ By these the 

 less savage but equally destructive tree-chafers {Melolonthce) , and those 

 enemies of vegetable beauty the rose-chafers (Cetonia niirnta), are enabled 

 to maintain their station on the trees and shrubs that they lay waste. 

 And by these also the water-beetles (Dytiscus, Hi/drophilus, &c.) climb 

 the aquatic plants. But it is unnecessary further to enlarge upon this 

 head ; I shall only observe, that in most of the insects here enumerated 

 the claws appear to be aided by stiff hairs or bristles. 



Other climbers ascend by means o( foot-cushions (pu/iu7//) composed 

 of hairs, as thickly set as in plush or velvet,'with which the under sides 

 of the joints of their tarsi — the claw-joint, which is always naked, except- 

 ed — are covered. These cushions are particularly conspicuous in the 

 beautiful tribe of plant-beetles (^Chrysomelidcc). A common insect of this 

 kind before mentioned, called the bloody-nose beetle (Timarcha tenebri- 

 cosa), by the aid of these is enabled to adhere to the trailing plants, the 

 various species of bedstraw (Galium), on which it feeds; and by these 

 will support itself against gravity ; for botli this and Chrysomela Goetting- 

 ensis will walk upon the hand with their 43ack downwards, and it then 

 requires a rather strong pull to disengage them from their station. The 

 whole tribe of weevils (Rhynchophora Lafr.) are also furnished with these 

 cushions, but not always upon all their joints, some having them only at 

 their apex; and the palm-weevil (Cordylia Palmarum) at the extremity 

 solely of the last joint but one. Those brilliant beetles the Buprestes 

 have also these cushions, as have likewise the numerous tribes of caprl- 

 corn-beetles (Longicorncs Latr,). The larva? of these being timber-borers, 

 the parent insect is probably thus enabled to adhere to this substance 

 whilst it deposits its eggs. Indeed in some species of the former genus 

 the cushions wear the appearance of suckers. Wliile the linear species of 

 Helops are without them, they clothe all the tarsi of H. ceneus (Chalciies 



' Reaum. ii. 457. 



