射炮步甲
名称射炮步甲（Brachinus）
(北美的Brachinus属以及非洲、亚洲和东印度群岛的Pherosophus属)
又名：投弹手甲虫(Bombardier Beetle)
分类（Classification）Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Adephaga (Ground and Water Beetles)
Family Carabidae (Ground Beetles)
Subfamily Brachininae
Tribe Brachinini
Genus Brachinus (Bombardier Beetle)
数量（Number）Genus has forty to fifty North American species--seeprint referencescited below.
体型（Size）5-13 mm
特征（Identification）Brachinus属种类的翅深蓝、黑或蓝绿色，身体和足浅红黄色。
射炮步甲在腹部末端有一个小囊，能喷出有毒的液体，用以防范天敌；射炮步甲将液体在极高的温度下放射出，炽热的液体一经接触空气就汽化；液体内含有毒的醌类，醌类在昆虫体内一个室中与过氧化氢(亦系昆虫产生，贮存在体内某处)猛烈反应，射液时发出「砰」的一声，更使敌人吃惊。
Medium-sized beetles with dark (blue, green, or blackish) elytra that contrast strongly with orange head and pronotum. Elytra are wider than pronotum. Some species flightless (1).
Mimicked by other ground beetles such as Galerita, and by some longhorned beetles.
分布北美、非洲、亚洲和东印度群岛
栖息地（Habitat）Found under loose bark, rocks, boards, etc. Also found on ground in open at night. Usually associated with floodplains, edges of temporary ponds.
活跃季节（Season）Typically spring, early summer and fall? March-July, September-October (B. alternans, South Carolina).
生命周期（Life Cycle）Eggs laid singly in mud cells made on plants, rocks. Larvae are external parasites of dytiscid beetles such as Hydrophilus. Larvae also scavenge body of host after its death. A few species parasitize whirligig beetles, Gyrinidae. Larvae have reduced legs, typical of parasitic forms. Pupation occurs inside the body of the host. Adults have impressive chemical defenses, ejecting toxic, foul-smelling gases from their abdomen with a loud popping sound. The explosive brew is composed of hydrogen peroxide, hydroquinone, and catalytic enzymes.
又见（see also）False Bombardier Beetles, Galerita
出版物资料（Print References）Ciegler, pp. 33-36, describes, keys to the 16 South Carolina species (1).
Sikes, pp. 76-77, lists 12 species for Rhode Island (2)
Dillon, pp. 107-108, plate XI, describes and illustrates two species (3).
Papp, p. 51, fig. 141--B. americanus (4)
Arnett and Jacques, p. 98, fig. 254 (5)
White, p. 94, fig. 31 (6)
Milne, p. 537, fig. 166 (7)
Internet资料（Internet References）Insects of Cedar Creek
National Center for Science Education--discussion of mechanism of chemical defenses
Clemson University--discussion of chemical defenses under account for Galerita
鸣谢（Works Cited）1. Ground Beetles and Wrinkled Bark Beetles of South Carolina
By Janet Ciegler
2. The Beetle Fauna of Rhode Island, an Annotated Checklist
By Derek Sikes
3. A Manual of Common Beetles of Eastern North America
By Dillon, Elizabeth S., and Dillon, Lawrence
4. Introduction to North American Beetles
By Charles S. Papp
5. How to Know the Beetles
By Ross H. Arnett, N. M. Downie, H. E. Jaques
6. Peterson Field Guides: Beetles
By Richard E. White
7. National Audubon Society Field Guide to Insects and Spiders
By Lorus and Margery Milne