MEANS OF DEFENCE OF INSECTS. 239 



plants and vegetable substances, insects, of any part of 

 the creation, afford the greatest diversity of odours. In 

 the Coleoptera order a very common beetle, the whirl wig 

 (Gyrinus Natator}, will infect your finger for a long 

 time with a disagreeable rancid smell ; while two other 

 species, G. minutus and villosus, are scentless. Those 

 unclean feeders, the carrion beetles (Silpha, L.), as might 

 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 

 mortisaga\ and which he recommends as an infallible 

 nostrum, when applied with oil extracted from the cedar, 

 in otherwise incurable ulcers, that was an object of ge- 

 neral disgust on account of its ill scent, a character which 

 it still maintains a . Numbers of the ground-beetles (JGw- 

 trechina) that are found under stones, and in places that 

 have not a free circulation of air, exhale a most disa- 

 greeable and penetrating odour, 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 5 ; but I am rather in- 

 clined 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 primrose ( 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\ belonging to the Orthoptera order, is 

 not remarkable for a pleasant scent ; but none are more 



* Hist. Nat. \. xxix. c. 6. b iv. 86. 



