COLLEMBOLA OF THE FAMILY ISOTOMIDAE 65 



(pi. 24, fig. 270) with a pair of linear feebly curving rods, a thick 

 chitinous ridge, and a pair of guard setae. Third abdominal segment 

 shorter than the fourth (as 5:6). Genital and anal segments anky- 

 losed. Unguis (pi. 24, fig. 271) simple, without lateral or inner 

 teeth. Unguiculus broadly lanceolate, acuminate, extending about 

 half as far as the unguis. Tenent hairs absent. Furcula slender, 

 gradually tapering, extending only as far as the middle of the second 

 abdominal segment. Manubrium three-fifths as long as dentes; 

 dorsaliy with a few short stiff setae; ventrally naked except for one 

 subapical pair of long setae. Dentes slender, tapering; dorsaliy with 

 a few basal setae and many crenulations, ending far from the apex; 

 ventrally with many stiff appressed setae. Mucro (pi. 24, fig. 272) 

 about as long as hind unguiculus, subequally bidentate; apical tooth 

 hooked, anteapical erect. Rami of tenaculum quadridentate ; corpus 

 with a single seta. General clothing of short stiff simple setae; erect 

 sensory setae short, simple. Maximum length, 1 .9 mm. 



Cotypes.—U.S.ISIM. no. 42979. 



Distribution. — Recorded as follows: 



Florida: Gainesville, January 12, in decaying leaves; Gainesville, February 20, 

 D. M. Bates. Camp Torreya, April 4; Rock Bluff, April 4, T. H. Hubbell. 



PROISOTOMA (PROISOTOMA) COGNATA, new species 



Plate 24, Figures 273-275 



Description. — General color bluish, greenish, or blackish; pigment 

 blue or blacldsh, mottled; anterior borders of body segments white; 

 posterior borders edged narrowly with blackish; antennae blue; 

 legs pale, feebly pigmented; furcula white. Eyes eight on each side, 

 on black patches, the two inner proximal eyes of each side smaller 

 than the others. Postantennal organ (pi. 24, fig. 273) subelliptical, 

 constricted at the middle, thick-walled, two and one-half times as 

 long as the diameter of an adjacent eye. Antennae a little longer 

 than the head, with segments in relative lengths about as 6 : 11 : 10 :22. 

 Sense organ of third antennal segment with a pair of slender curving 

 rods, subtended by a chitinous ridge. Fourth antennal segment 

 without special olfactory setae; with a terminal tubercle. Fourth 

 abdominal segment longer than the third (as 3:2). Genital and anal 

 segments ankylosed. Unguis (pi. 24, fig. 274) slender, weakly curv- 

 ing, without lateral or inner teeth. Unguiculus broadly lanceolate, 

 acuminate, untoothed, extending half as far as the unguis on the 

 hind feet; two-fifths as far on the other feet. Tenent hairs absent. 

 Furcula extending to the middle of the second abdominal segment. 

 Manubrium stout, dorsaliy with numerous short stiff setae, ventrally 

 with one pair of stout subapical setae. Dens not quite twice so long 

 as manubrium, slender, tapering, dorsaliy with numerous fine crenula- 

 tions except proximally and distally, and a few stiff setae; ventrally 



