152 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 



hand. X, p. 46. Uzel. Litzber, k. boh. Gesell, wiss. II, p. 63, 



1891. 

 Isotoma paliistris var. fusca Tullberg, k. sven. vet. Akad. hand., 



X, no. 10, p. 46, 1872. Uzel. Litzber, k. boh. Gesell, wiss., II, 



p. 63, 1891. 

 Isotoma helfragei Packard, Fiftli Eep. Trust Peab. acad., pp. 



33-34, 1873. MacGillivray, Can. ent., XXIII, p. 273, 1891. 

 Isotoma tricolor (in part) Packard, Fifth Rep. Trust Peab. 



acad., p. 34, 1873. MacGillivray, Can. ent. XXIII, p. 273, 



1891. 

 Isotoma purpurescens Packard, Fifth Rep. Trust Peab. acad., 



pp. 34-35, 1873. MacGillivray, Can. ent., XXIII, p. 274, 1891. 

 Isotoma plumbea Packard, Fifth Rep. Trust Peab. acad., p. 35, 



1873. MacGillivray, Can. ent., XXIII, p. 274, 1891. 

 Isotoma palustris Tullberg, Ofv. k. vet. Akad., fork., XXXIII, 



]ip. 34-35, 1876. 



Description: Length — 5-6 mm. Color — Either yellow marked 

 with puri)le or dark brown. Antennas — Half as long again as 

 the body; IV longest, II and III equal, I shortest. Ocelli — 

 Sixteen. Postantennal organ — Ovate to oval. Claws — Superior, 

 long, slender, tapering, armed with two teeth on the inner 

 margin and one on the outer; inferior less than half as long, 

 acute, apically curving, armed on inner margin; tenent hair 

 unknobed. Furcula — Half as long as body; dentes nearly three 

 times manubrium in length; mucrones tridentate with the teeth 

 subequal, large, blunt; apical tooth falcate, second and third 

 subfalcate and opposite each other. Integument — Dense, short 

 curving seta?, with long bai-bellate hairs on the posterior part 

 of the abdomen. 



Variation: There is great variation in this species and I 

 expect to consider this at another time. 



Habitat: Found in great abundance in the entire region from 

 the mountains to the sea. 



Isotoma catena Guthrie - 



(Plate II, Figs. 6-7) 

 Isotoma catena Guthrie 1903. The C^ollembola of Minnesota, 

 geol. and nat. hist. surv. of Minn, zooh series 4, p. 69. 



