COLLEMBOLA OF THE FAMILY ISOTOMIDAE 57 



rounded apically, with coarse intermediate dorsal crenulations, with 

 a few short dorsal setae and a few lateral and subapical ventral setae. 

 Mucrones (pi. 21, fig. 227) tridentate; apical tooth the smallest, 

 almost straight or slightly hooked; second and third subequal, sub- 

 conical, erect; third more lateral than the second; ventral margin in 

 lateral aspect almost straight except distally. Clothing (pi. 21, 

 fig. 228) of short curving reclinate setae, longer posteriorly; sensory 

 setae long, outstanding. Integument smooth but reticulate. Length, 

 1.1 mm. 



Remarks. — The only examples of this species that I have seen are 

 three cotypes: One belonging to the Museum of Comparative 

 Zoology, Cambridge, Mass.; one to Cornell University; and one 

 given to me by Dr. MacGillivray. In the first-mentioned cotype the 

 legs and furcula are white; in the other two they are marked with 

 pale violet, and the antennae are whitish with more or less purple, 

 especially distally. 



Distribution. — Recorded as follows: 



Ohio: Salineville, February 2, A. D. MacGillivray (Museum of Comparative 

 Zoology; Cornell University). 



PROISOTOMA (PROISOTOMA) VESICULATA. new species 



Plate 21, Figures 229-232; Plate 22, Figures 233-237 



Description. — Head and body blackish blue; body with narrow 

 white intersegmental bands; appendages paler blue; coxae blacldsh. 

 Less heavily pigmented individuals may be mottled with white spots, 

 with antennae and legs yellow distally and blue proximally. Body 

 and appendages stout. Eyes (pi. 21, fig. 229) eight on each side, the 

 two inner proximal eyes smaller than the others. Postantennal 

 organ (pi. 21, fig. 229) situated close to the antennal base, subeUiptical, 

 about one-fourth longer than the diameter of one of the largest eyes, 

 with a notch near the middle of the anterior margin. Antennae 

 subequal to head in length, or slightly longer than head, with seg- 

 ments in relative lengths about as 8:10:11:21, or 6:7:7:16; third 

 segment occasionally slightly shorter than the second. Sense organ 

 of third antennal segment as in figure 230. The curving setae of the 

 fourth antennal segment are strong, but not evidently modified to 

 form olfactory setae. Tibiotarsus without a distal subsegment. 

 Unguis (pi. 21, fig. 231) with a pair of strong lateral teeth and a tooth 

 behind the middle of the inner margin. Unguiculus extending two- 

 thirds as far as unguis on hind feet, acute, with an inner angle tooth. 

 One long tenent hair, feebly knobbed, extends as far as the inner 

 tooth of the unguis. Third abdominal segment shorter than the 

 fourth (as 7:10). Genital and anal segments ankylosed, with in some 

 cases a trace of a dorsal suture. Furcula (pi. 21, fig. 232) stout, 

 appended to the fifth abdominal segment, not attaining the ventral 

 tube, but extending to the middle of the second abdominal segment. 



