542 



BOMBARDIER BEETLE BOMBAX. 



baobab or monkey's bread, tbe largest known tree, 

 whose trunk has been found nine'ty feet in circum- 

 ference. The particulars in regard to this tree and 

 its uses, are fully detailed under the article ADAN- 

 SONIA. 



The genus Helicterps receives the name of screw- 

 tree from its curious spiral seed-vessels. Ckciros- 

 temon, or the hand-plant of Mexico, has its name 

 from the five bundles of stamens being thick, coloured, 

 and turned on one side so as to resemble a paw with 

 five claws. Ochroma, and the genus of the order, is 

 so called on account of its yellow flowers. Ochroma 

 lagopus is a large tree with diverging branches, and 

 leaves more than a foot long. Its wood is so light 

 as to serve for corks to nets. Its capsules contain a 

 soft down, which is used in the manufacture of English 

 beavers. The seeds of several of the species included 

 in this order are enveloped in long hairs, like those 

 of the true cotton. They cannot, however, be used 

 in manufacture, owing to the want of adhesion be- 

 tween the hairs. The hairs are quite smooth, not 

 rough and feathery like those of the cotton plant. The 

 woolly matter furnished by the Bombax ceiba, Cho- 

 risia speciosa, and several other species, is used for 

 stuffing chairs and cushions. 



Any medical properties which the plants of this 

 order possess seem to depend solely on the mucilage 

 which they contain. 



BOMBARDIER BEETLE. Under this name 

 the species of the coleopterous genus Brachinus are 

 known. These insects, whose generic character will 

 will be found under their generic name, possess a very 

 remarkable power, enabling them to defend themselves 



Bombardier Beetle. 



against the attacks of their enemies. The British 

 species are of a rather small size, being under half an 

 inch in length, of a blue-black colour, with the thorax 

 of a red or yellowish colour. In general, they con- 

 ceal themselves beneath stones ; but when they are 

 disturbed, one is surprised to hear a noise resembling 

 the explosion of a" musket in miniature, accompanied by 

 a considerable discharge of bluish smoke frqm the anus. 

 Many of the carabidae have the power of ejecting an 

 acrid and caustic fluid, but in the brachinus this is so 

 extremely volatile, that it evaporates immediately on 

 coming into contact with the air. It is, moreover, of 

 so pungent a nature, as to irritate any part of the body 

 upon which it may happen to fall, tinging the skin 

 with a dusky mark, which remains for several days, 

 and causing a most violent pain if it happen to touch 

 the eyes. Indeed, according to M. Leon Dufour, 

 who has studied the structure of these insects with 

 particular care,.the odour of this vapour has a striking 

 analogy with that exhaled by nitric acitl, and is 

 caustic, reddening white paper. The insect, notwith- 

 standing the assertion of Mr. Millard to the contrary 

 (Outlines of British Entomology, p. 221.), not only 

 possesses the power of causing this discharge when 

 handled, but is able to repeat it successively for a 

 considerable number of times,. Solarfder, who first 

 observed it, says twenty. (Mem. Acad. Stockholm. 

 1750); and Mr. Cooper, the celebrated R.A., counted 



thirteen discharges in rapid succession (Stephens' 

 Illustrations Brit. Ent., I, 35). The discharges, how- 

 ever, become less violent, and afterwards, instead of 

 smoke, merely a brown or yellow fluid is emitted, as 

 if the more elaborately concocted liquid had been 

 consumed. The insect may be made to play off its 

 artillery at any time, by scratching its back with a 

 needle ; and by bending the segments of the abdomen, 

 it is able to direct the smoke in any direction. It is 

 in self-defence that these discharges are generally 

 made, since, like many of the smaller carabidas, the 

 bombardier beetles are preyed upon by the larger 

 species of the same family. When pursued, then-fore, 

 and on the point of being seized by its enemy, it has 

 recourse to this stratagem, by lying in its pursuer's 

 path, which advances with open mouth to seize if, and 

 by immediately discharging its amrniinitioi!. ('tin- 

 founded by the scent, and unable to see from the 

 smoke, the enemy draws back until it has recovered 

 from its effects, when the pursuit is renewed, and a 

 second discharge takes place, and which is continued, 

 either until the brachinus has gained a place of saf'etv, 

 or the pursuer is enabled to seize its prey, which "it 

 immediately destroys by tearing off the head. 



M. Dufour has given a very minute account of the 

 internal structure whence this explosive fluid is pro- 

 duced in Brachinus hallsta (Annales du Musee, vol. 

 xviii, p. 70, and Bulletin des Sciences, Soc. Phil. July 

 18f*2) and which consists of a double apparatus, accord- 

 ing to Messrs. Kirby and Spence (whose abridged ac- 

 countwe have thought most suitable), one on each side 

 in the cavity of the abdomen, both formed of two dis- 

 tinct vessels. The first, which is the innermost, 

 presents itself under two different aspects, according 

 as it is contracted or dilated ; in the former case it 

 is a whitfsh irregularly rounded, soft body, apparently 

 glandular, placed under the last abdominal segments, 

 communicating at one end with the reservoir, and 

 terminating constantly at the other in a very long and 

 slender filament ; in the second case, or when it is 

 dilated, it resembles an oblong, membranous diapha- 

 nous sac, filled with air, then occupying the whole 

 length of the abdomen, and appearing free except 

 where it communicates with the reservoir. The se- 

 cond vessel or reservoir is a small spherical brown or 

 reddish body, constant in its form, internally hollow, 

 placed under the last dorsal segment, precisely above 

 the rectum, and opening by a small pore into the 

 anus, so that the tail of this little beetle may be re- 

 garded as a battery mounted with two pieces of 

 cannon, which our alert bombardiers fire alternately 

 without intermission until all their ammunition is 

 expended. 



The generic name is derived from the Greek, and 

 signifies to make a noise ; and in allusion to this pro- 

 perty some of the- species are named fumigatus, 

 crepitans, sclopeta, causticus, explodens, bombarda, 

 exhalans, &c. 



BOMBAX (Linnaeus). The silk cotton tree be- 

 longs to the class and order Monadelphia Poli/andria, 

 and natural order Bombatece. Generic character : 

 calyx nearly bell or pitcher shaped, abbreviated, ir- 

 regularly from three to five-cleft ; petals five, over- 

 lapping each other at the base ; filaments united in 

 bundles ; anthers adnate or versatile, sometimes kid- 

 ney-shaped, two-celled ; style simple ; stigma headed, 

 lobed ; capsule woody, five-celled, five-valved ; cells 

 filled with silky cotton ; dissepiments central, seeds 

 several. In addition to what has been observed of 



