34 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



2. Tenent hairs absent. Manubrium longer than dentes. Dentes 

 rounded apically. Ventral margin of mucro not strongly 



curving, in lateral aspect antiqua (p. 34) 



Tenent hairs present. Manubrium equal to, or shorter than, 

 the dentes. Dentes not rounded apically. Ventral margin 

 of mucro strongly curving vetusta (p. 35) 



GUTHRIELLA ANTIQUA, new species 



Plate 9, Figures 89-99 



Description. — Dark blue, with bulging segments (pi. 9, fig. 89), 

 the intersegmental constrictions being deeper than in other Iso- 

 toniidae, except G. muskegis. Body stout. Antennae blue; legs 

 white distally, pigmented basally; manubrium pigmented; dentes 

 usually white. Eyes (pi. 9, fig. 90) eight on each side, on black 

 patches. Postantennal organ (pi. 9, fig. 90) elliptical, one and 

 one-half to three times as long as the diameter of an adjacent eye. 

 Antennae subequal to head or a little shorter (as 7:8); segments in 

 relative lengths about as 8:12:13:19, Sense organ of thu'd antennal 

 segment (pi. 9, fig. 91) with a pair of curving rods subtended by a 

 thick ridge, and \vith two linear curving rodlike accessory setae. 

 Fourth antennal segment with many olfactory setae (as many as 16) 

 and an apical hemispherical sensory tubercle. Pronotum with folds, 

 tuberculate, not membranous. Terga not mibricate. Abdominal 

 segments without ankylosis; abdomen dilated. Fourth abdominal 

 segment longer than the third (as 3:2). Tibiotarsus with a distal 

 subsegment. Unguis (pi, 9, fig, 92) slender, without lateral or inner 

 teeth, Unguiculus (pi. 9, fig. 93) extending two-fifths to three- 

 fifths as far as the unguis, broadly lanceolate, acute, untoothed, 

 with two inner lamellae. Tenent hairs absent. Furcula appended 

 to the fifth abdominal segment, extendmg not quite to the ventral 

 tube. Manubrium stout, but not swollen basally, with several 

 dorsal setae but naked ventrally, with a pair of ventral subapical 

 hooks and a pair of ventroapical paramedian teeth (pi. 9, fig. 94). 

 Dentes (pi. 9, fig. 95) shorter than manubrium (as 5:6 or 5:7), stout, 

 Bubcylindrical, not bowed or convergent, not tapering, apically 

 rounded, with few dorsal setae, with stifi' ventral and lateral setae 

 on distal half, dorsally without transverse folds, but with numerous 

 low tubercles, larger than the other cuticular tubercles. Mucro 

 (pi. 9, figs. 96-98) one-third as long as dens, bidentate, bilamellate; 

 apical tooth short, upcurved; anteapical tooth median dorsal; the 

 outer and inner lamellae extend from the anteapical tooth to the 

 base of the mucro. Rami of tenaculum quadridentate; corpus with 

 a single curving ventral seta. Clothing of abundant minute curving 

 setae (pi. 9, fig. 99) with a few setae longer than the others on the 

 anal segment; long erect sensory setae absent. Integument finely 

 tuberculate. Length, 0,9 mm. 



