18 COLEOPTERA OF NORTH AMERICA. 



Tribe I.— RRAC IBIMM. 



The increased number of ventral segments (seven in the female, 

 eight in the male) will readily distinguish the members of this tribe. 

 Additional characters are : The paraglossa? are scarcely longer 

 than the ligula; the elytra are truncate at tip, and shorter than 

 the abdomen ; the anterior tibiae are slender, not spinous at the tip, 

 and the anterior tarsi of the male have three slightly dilated joints, 

 with squamiform papillas on the under surface. Of the antennas 

 the first and second joints are smoother than the others, but not 

 altogether without hair. The head and thorax are narrower than 

 the elytra, and the thorax is cordate. 



These insects are found in damp and shady places, under stones, 

 &c, and are remarkable for discharging, in an explosive manner, 

 a pungent fluid secreted by anal glands. 



But one genus, Brachinus, is found in the United States. The 

 species are numerous, and the specific characters are indistinct. 

 They all have reddish-yellow head, thorax, and legs, and blue or 

 bluish-green elytra. 



Tribe II.— PANAG^OJI. 



Besides the absence of the usual ocellate punctures near the 

 margin of the elytra, the following characters enable this tribe to 

 be recognized; the ligula is short, without distinct paraglossse; 

 the last joint of the palpi is dilated and truncate; the elytra are 

 entire, neither truncate nor sinuate at the tip; the anterior tarsi of 

 the male, when dilated, are spongy beneath. The first and second 

 joints of the antenna? are glabrous, the third not so, although 

 smoother and less hairy than the fourth. The mentum is toothed 

 in our species, and smaller than usual. The thorax is constricted 

 at base, and the abdomen almost pedunculated. The epimera of 

 the metathorax are not very distinct. The body above and beneath 

 is coarsely punctured and pilose. 



Two genera are found in our territory : — 



Head constricted behind the eyes ; mandibles short, acute. Panaceus. 

 Head not constricted behind ; mandibles thick, obtuse. Micrixys. 



Of the first, two species are found in the Atlantic States. The 

 second genus is known only by one species, M. distinctns Lee. 

 (Panagceus distinctus Hald.), from New Mexico. The genus was 



