JSIEANS OF DEFENCE OF INSECTS. 415 



MalacMus endeavour to alarm tlieir enemies and show their rajje by puff- 

 ing out and inflating four vesicles from the sides of their body, which are of 

 a bright red, soft, and of an irregular shape. When the cause of alarm is 

 removed, they are retracted, so that only a small portion of them ap- 

 pears.^ 



Insects often endeavour to repel or escape, from assailants by their motions. 

 Mr. White, mentioning a wild bee that makes its nest on the summit of 

 a remarkable hill near Lewes in Sussex, in the chalky soil, says : — " When 

 people approach the place these insects begin to be alarmed, and with a 

 sharp and hostile sound dash and strike roimd the heads and faces of in- 

 truders. I have often been interrupted myself while contemplating the 

 grandeur of the scenery around me, and have thought myself in danger of 

 being stung." ^ — The hive-bee will sometimes have recourse to the same 

 expedient, when her hive is approached too near, and thus give you notice 

 what you may expect if you do not take her warning and retire. — 

 Humble-bees when disturbed, whether out of the nest or in it, assume 

 some very grotesque and at the same time threatening attitudes. If you 

 put your finger to them, they will either successively or simultaneously 

 lift up the three legs of one side ; turn themselves upon their back; bend 

 up their anus and show their sting accompanied by a drop of poison. Some- 

 times they willl even spirt out that liquor. When in the nest, if it be at- 

 tacked, they also beat their wings violently and emit a great hum.' 



These motions menace vengeance ; those of some other insects are 

 merely to effect their escape. Thus I have observed that the species of 

 the May-fly tribe {Tric/ioptera ■*), when I have attempted to take them, have 

 often glided away from under my hand — without moving their limbs that 

 I could discover — in a remarkable manner.^ M. de Villiers informs us 

 that different species of moths of the genera Orthosia and Cerastis never 

 avail themselvesof their wings to escape the dangers which threaten them ; 

 but if you attempt to seize them immediately let themselves fall to the ground, 

 and then begin running with such rapidity, that it is very difficult to obtain 

 possession of them.® And in like manner various CurcuUonldce and other cole- 

 opterous insects, if they see any one approach, contract their legs, and suffer 

 themselves to fall from the leaf or other surface on which they rest,among the 

 grass or plants below, and thus escape. To notice the ordinary motions of 

 insects, which are often means by which they avoid danger, would here be 

 premature, since they will be fully considered in a subsequent letter. I 

 shall, therefore, only mention the zigzag flight of butterflies and the traverse 

 sailingof humble-bees, which certainly render it more difficult for the birds 

 to catcii them while on the wing. 



Noises are another means of defence to which insects have occasional 

 recourse. I have heard the lunar dung-beetle {Copris lunaris), when dis- 

 turbed, utter a shrill sound. Di/nastcs Oromedon, another of the lamel- 

 licorn insects, was observed by Dr. Arnold to make, when alarmed, a kind 

 of creaking noise, which it produced by rul)bing its abdomen against its 

 elytra. A third of the same tribe (Trox sabulosiis) emits a small sibilant or 

 chirping noise, as I once observed when I found several feeding in a ram's 



1 De Geer, iv. 74. 2 Nat. Hist. ii. 268. 



5 P. Huber, in Linn. Trans, vi. 219. Kirby, Man. Ap. Angl. i. 201. 



* Kirb}' in Linn. Trans, xi. 87. note *. 



* Evicfently by tlie action of the numerous spines on the legs all directed back- 

 wards, just as an ear of barley will mount up the sleeve of a coat. 



* Ann. Soc. JEnt de France, xi. bull. xii. 



