532 FAMILY XVIII. — PLOIARIID^. 



species usually placed about the basal third, this followed in 

 front by numerous shorter ones, very irregular in length (fig. 

 32) ; tibiae and tarsi subequal in length, united about half the 

 length of femora (fig. 33) ; middle and hind legs filiform, their 

 femora not or but slightly passing tip of abdomen. Male with 

 last dorsal projected backward in the form of an elongate-oval 

 shield to cover wholly or in great part the genital segment 

 (figs. 35 and 40). 



The members of this genus are hygrophilous or semi-aquatic, 

 occurring mostly beneath cover in low moist places, or occasion- 

 ally even on the surface of water. Our species have heretofore 

 been recorded under the genus Barce Stal (1865, 162) . McAfee 

 & Malloch have replaced this name with Metapterus, the genus 

 Barcc not being represented in America. Only seven American 

 species of Metapterus are known, five from our territory. 



KEY TO EASTERN SPECIES OF METAPTERUS. 



a. Front femora distinctly stouter than front coxa? and either annulate 



or spotted with dark and pale; under surface of head with a 



yellowish stripe; color not a nearly uniform opaque black. 



b. Under surface of head with a pale yellowish stripe which is not 



narrower than interocular space and not interrupted by a dark 



spot on each side behind eye; upper margin of genital plate of 



male with a subquadrate, slightly emarginate backward curved 



process (fig. 34) and without an erect spine within the upper 



border. 



c. Middle and hind femora each annulated with several brown rings ; 



median carina of mesonotum vaguely defined ; seventh dorsal of 

 male abdomen with apex obtusely rounded, not projecting be- 

 yond the apex of genital (fig. 35). 507. ANNULIPES. 

 cc. Middle and hind femora each with but a single preapical dark 

 ring; median carina of mesonotum distinct; seventh dorsal of 

 male with apex more acutely rounded, projecting more or less 

 beyond the apex of genital (fig. 37). 508. fraternus. 

 66. Under surface of head with a pale yellowish stripe which is nar- 

 rower than interocular space, or is interrupted by a distinct dark 

 spot each side behind eye; upper margin of genital plate of male 

 not produced backward at apex, and with a long spine within its 

 upper border (figs. 41 and 43). 



d. General color dark fuscous-brown; surface rugulae of abdomen, 



both above and below, reticulated; apical spine of genital plate 

 of male distinctly curved backward at tip (fig. 40). 



509. UHLERI. 



dd. General color straw-yellow; surface rugulae of abdomen chiefly 



longitudinal, not reticulated; apical spine of genital plate 



straight or almost so (fig. 44). 510. neglectus. 



