MEANS OF DEFENCE OF INSECTS. 237 



often glided^. way from under my hand without moving 

 their limbs that I could discover in a remarkable man- 

 ner. I once observed a short-snouted weevil (Brachy- 

 rhynchm, Schon.) upon a rail, which, when it saw me, 

 slided sideways, and then rolled off. To notice the or- 

 dinary motions of insects, which are often means by which 

 they escape from danger, would here be premature, since 

 they will be fully considered in a subsequent letter. I 

 shall therefore only mention the zigzag flight of butter- 

 flies and the traverse sailing of humble-bees, which cer- 

 tainly render it more difficult for the birds to catch them 

 while on the wing. 



Noises are another mean of defence to which insects 

 have occasional recourse. I have heard the lunar dung- 

 beetle (Copris lunaris] when disturbed utter a shrill 

 sound. Dynastes Oromedon, another of the lamellicorn in- 

 seets, was observed by Dr. Arnold to make, when alarm- 

 ed, a kind of creaking noise, which it produced by rub- 

 bing its abdomen against its elytra. A third of the same 

 tribe, ( Trox sabulosus) emits a small sibilant or chirp- 

 ing noise, as I once observed when I found several feed- 

 ing in a ram's horn. The "drowsy hum" of beetles, hum- 

 ble-bees, and other insects, in their flight, may tend to 

 preserve them from some of their aerial assailants. And 

 the angry eludings of the inhabitants of the hive, which 

 are very distinguishable from their ordinary sounds, may 

 be regarded as warning voices to those from whom they 

 apprehend evil or an attack. I have before observed that 

 the death's-head hawk-moth (Acherontia Atropos\ when 

 menaced by the stings of ten thousand bees enraged at 

 her depredations upon their property, possesses the secret 



