452 MEANS OF DEFENCE OF INSECTS. 



In the Coleoptera order a very coainion beetle, the whlrlwig (Gyrinus 

 naintor), will infect your finger for a long time with a disagreeable rancid 

 smell; while two other species, G. minutus and viUosus, are scentless. 

 Those unclean feeders, the carrion beetles (^Siljjha L.), as migiit be 

 expected from the nature of their food, are at the same time very fetid. 

 Pliny tells us of a Blatta, which, from his description, is evidently the 

 darkling-beetle {Blaps mortisagd) , and which he recommends as an infal- 

 lible nostrum, when applied with oil extracted from the cedar, in other- 

 wise incurable ulcers, that was an object of general disgust on account of 

 its ill scent, a character which it still maintains^ ; which scent, from Mr. 

 Thwaites's investigation of the internal anatomy of this insect, proceeds 

 from two small oblong vesicles near the anus, the fluid contents of which, 

 when they are extracted and dissected under water, rise in a bubble to 

 the surface, and there becoming vaporized diffuse the fetid smell peculiar 

 to this species. Numbers of the ground-beetles (^Eutrechina) that are 

 found under stones, and in places that have not a free circulation of air, 

 exhale a most disagreeable and penetrating odor, which De Geer observes 

 resembles that of rancid butter, and is not soon got rid of. It is produced, 

 he says, from an unctuous matter that transpires through the body^; but 

 I am rather inclined to think it proceeds from the extremity. I have 

 noticed that some small beetles of the Omalium genus, for instance O. 

 rivulare, and another species that I once found in abundance on the prim- 

 rose (O. Primula K. Ms.), especially the latter, are abominably fetid 

 when taken, and that it requires more than one washing to free the fingers 

 from it. Every one knows that the cock-roach {Blatta orientalis), belong- 

 ing to the Orthoptera order, is not remarkable for a pleasant scent; but 

 none are more notorious for their bad character in this respect than the 

 bug tribe (Geocomce), which almost universally exhale an odor that mixes 

 with the scent of cucumbers another extremely unpleasant and annoying. 

 Some, however, are less disgusting, particularly Lygams Ilyoscyami, which 

 yields, De Geer found, an agreeable odor of thyme. ^ — Several lepidopte- 

 rous larvae are defended by their ill smell ; but I shall only particularize 

 the silk-worms, which on that account are said to be unwholesome. — Phry- 

 ganea grandis, a kind of May-fly, is a trichoptcrous insect that offends 

 the nostrils in this way ; but a worse is Chrysopa Pcrla, a golden-eyed 

 and lace-winged fly, of the next order, whose beauty is counterbalanced 

 by a strong scent of human ordure that proceeds from it. — Numberless 

 Hymenoptera act upon the olefactory nerves by their ill or powerful efflu- 

 via. One of them, an ant (Formica fcetida De Geer, foitens Oliv.), has 

 the same smell with the insect last mentioned."* Our common black ant 

 {F. fuliginos a), whose cimous nests in trees have been before described 

 to you, is an insect of a powerful and penetrating scent, which it imparts 

 to every thing with which it comes in contact ; and Fabricius distinguishes 

 another (F. analis hntr., fceteiis F.) by an epithet (/(etidissima) -which 

 sufficiently declares its properties. Many wild bees (Andrena) are dis- 

 tinguished by their pungent alliaceous smell. Crahro U-flavum, a wasp- 

 like insect, is remarkable for the penetrating and spirituous efiiuvia of ether 

 that it exhales.^ Indeed there is scarcely any species in this order that 



» Hist. Nat. 1. xxix. c. 6. ^ iv 8fi. 3 De Geer, iii. 249. 374. 



* De Geer, iii. 611. * Kirby, Mon. Ap. Angl. i. 136. note a. 



