Collembola of the Canadian Arctic Expedition, 1913-18. 
By Justus W. Folsom 
Of the University of Illinois. 
This is a report on the Collembola obtained by the Canadian Arctic Expe- 
dition, 1913-16. The material, collected by Mr. F. Johansen, consisted of 
numerous well-preserved specimens, in excellent condition for study, and com- 
prised the following twelve species: — 
Podura aquatica L. 
Achorutes tullbergi Schaf. 
Achorutes sensilis, n. sp. 
Achorutes armatus (Nic.) 
Onychiurus duodecinipiinctatus, n. sp. 
Tetracanthella iDahlgreni Axels. 
Folsomia quadrioculata (Tull.). 
Isotoma viridis Bourl. 
Isotoma palustris (Miill.). , 
Entomohrya comparata, n. sp. 
Lepidocyrtus cyaneus TulL 
Sjninthurides aquaticiis (Bourl.). 
The types and other specimens upon which this report is based are deposited 
in the National Collection of Insects, Ottawa. 
Podura aquatica Linnaeus. 
■ Plate 1, figs. 1-3. 
Podura aquatica Linnaeus, 1758.— Nicolet, 1841.— Tullberg, 1871, 1872.— 
Lubbock, 1868, 1873.— Packard, 1873.— Parona, 1879, 1882.— Dalla Torre, 
1888, 1895.— Uzel, 1890.— MacGilhvray, 1891.— Schott, 1894, 1902.— Renter, 
1895.— Schaffer, 1896, 1900a, 1900b. — Lie-Pettersen, 1896— Poppe and Schaffer, 
1897.— Scherbakov, 1898b.— Carl, 1899, 1901.— Wahlgren, 1899c, 1906a.— 
Carpenter and Evans, 1899.— Absolon, 1900, 1901.— Willem, 1900.— Borner, 
1901a.— Krausbauer, 1901.— Agren, 1903.— Guthrie, 1903.— Axelson, 1906.— 
(Axelson) Linnaniemi, 1907, 1912. — Folsom, 1916. 
Hypogastrura aquatica Bourlet, 1839. 
Hydropodura aquatica Borner, 1901b, 1902. 
Podura granulata MacGillivraj', 1893. 
Blackish blue; antennae and legs reddish brown; furcula pale brown. 
Head hypognathous. Eyes 8 -F 8. Ocular areas with conical elevations 
between the eyes. Postantennal organs apparenth^ absent, represented extern- 
ally by minute rudiments. Antennae shorter than the head, stout, cylindrical, 
with segments about as 4:5:6:7. in relative lengths. Olfactory hairs of fourth 
antennal segment absent. Sense organ of third antennal segment consisting of 
a pair of short stiff setae. Body short and stout. A dorsal subsegment occurs^ 
on the anterior part of each body segment except the ninth. L''nguis (fig. 1) 
very long, longer than the tibio-tarsus, slender, ciu'ving, unidentate behind the 
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