ADEPHAGA AMPHIZOIDAE PELOBIIDAE 



207 



genera ; the Carabides are next in importance, with upwards of 

 2000 species, but are divided into a comparatively large number of 

 tribes, each of which averages a much smaller number of genera 

 than do the tribes of Harpalides ; Pseudomorphides includes only 

 about 100 species ; and Mormolycides consists of the single genus 

 Mormolycc with three species. 



Fam. 6. Amphizoidae. — Antennae destitute of pKhescence : 

 outer lohc of niaxUIa. not jointed; metasternum with a short 

 transverse impressed line on the middle hehind. Mind legs slender, 

 not formed for siviviming. This family is limited to the genus 

 Amp)hizoa ; the species of 

 which may be briefly de- 

 scribed as lowly organised 

 Carabidae that lead an 

 aquatic life. The geo- 

 graphical distribution is 

 highly remarkal)le, there 

 being but three species, two 

 of which live in Western 

 North America, tlie third 

 in Eastern Tibet. The 

 habits of American Avi- 

 2)hizoa are known ; they pass 

 a life of little activity in 

 very cold, rapid streams ; 

 they do not swim, but 

 cling to stones and timber. 



The larva was recently discovered in Utah by Messrs. Hul)bard 

 and Schwarz : ^ it has the same habits as the perfect Insect, 

 and in general form resembles the larvae of the genus Carahtis ; 

 but it has no terminal tube to the body, the abdomen consisting 

 of eight segments and a pair of short terminal appendages ; the 

 spiracles are obsolete, with the exception of a pair placed near to 

 one another at the termination of the eighth abdominal segment. 

 As regards the mouth this larva is Carabid, as regards the 

 abdomen and stigmata Dytiscid of a primitive type. 



Fam. 7. Pelobiidae. — Antennae destitute of pubescence : outer 

 lobe of maxilla Jointed, metasternum with a short transverse 

 impressed line on the middle behind. Hind legs rather slender, 

 ^ P. cut. Soc. JFashiiujfon, ii. 1892, p. 341. 



Fig. 93. — Amphizoa lecontei. North America. 

 A, Larva ; B, imago. 



