COLEOPTEBOTTS INSECTS. 119 



Such as exhibit a formation of this kind constitute 

 the section Truncatipennes. Some of the species 

 have attracted much attention in consequence of a 

 very singular means they employ to repel the at- 

 tacks of their assailants. The majority of carabide- 

 ous insects secrete an acrid and caustic fluid, which, 

 when irritated, they discharge with considerable 

 force. But in the kinds alluded to (belonging 

 chiefly to the genus Brachinus), the fluid is so vo- 

 latile, that when it is propelled by the insect it im- 

 mediately evaporates with a detonating sound, so 

 that the discharge seems to consist of blue smoke, 

 which is of a peculiarly disagreeable and penetrat- 

 ing odour. These bombardiers, as they are named 

 by the French, can fire a considerable number of 

 volleys before their ammunition is exhausted. The 

 largest kinds inhabit tropical and other warm coun- 

 tries ; but a few extend pretty far to the north, there 

 being several indigenous to France and the south 

 of England. 



To the section with truncated elytra belongs also 

 the genus Ant hi a (a name originally applied by 

 Aristotle to a kind of fish), which, however, does 

 not well exemplify the distinctive feature of this 

 subdivision, as the elytra are sinuated rather than 

 truncated at the extremity. It is known by having 

 the terminal joint of the external palpi somewhat 

 cylindrkal and truncated, or in the shape of a re- 

 versed cone ; by the want of a tooth in the notch 

 of the mentum ; and by the elongate-ovate form of 



