16 A Canadian Arctic Expedition, 1913-18 
corpus with a large anterior lobe extending below the rami, and bearing a pair 
of long anterior setae and a pair of short apical setae. Clothing of curving setae 
of moderate length, longer on the posterior part of the abdomen. Ano-genital 
segment with two slender simple sensory setae on each side. Integument tuber- 
culate. Length: female, 1 mm.; male, 0.5 mm. 
In small specimens the antennae are shorter than the head. The number 
of teeth of the inner dorsal lamella increases with age. Thus a female specimen 
4 mm. in length had seven teeth, and one 0.9 mm. had seventeen. 
The many specimens that I have seen from the United States and Canada 
agree with the e.xamples that I have received from Europe. 
Sminthurides aquaticus var. levanderi Reuter. 
Sminthurus apicalis var. Levanderi Reuter, 1891. 
Sminthurus aquaticus var. levanderi Schott, 1894. — Krausbauer, 1902. 
Sminthurides aquaticus var. levanderi Borner, 1901a. — Axelson, 1904, 
1905a.— Wahlgren, 1906a, 1906b.— (Axelson) Linnaniemi, 1907, 1909, 1911, 
1912. 
Light or dark violet in colour; in other respects like the typical form. 
The specimens collected by the Expedition belong to this variety', levanderi, 
and were all females, about half-grown. 
The genus Sminthurides comprises a few species, that are of special interest 
in several wa3^s. In this genus, as illustrated by *S. aquaticus, the persistence of 
traces of segmentation in the abdomen, an archaic character (Willem, '00), helps 
us to understand the morphology of the trunk, in the more specialized sminthuricls. 
The antennae of the male, with their peculiar hooks and tubercles, are modified 
to encircle and to hold those of the female at copulation, as described by Reuter 
('80) and Levander ('94). 
*S. aquaticus, like the other species of its genus, lives on the surface of the 
water of ponds and streams, where it skips about in a lively manner, owing to 
structural adaptations of the furcula, particularly the large paddle-like mucrones. 
The species frequents the leaves of various aquatic plants, but occurs sometimes 
on pools where there is no visible vegetation. A few specimens that I examined 
at one time had desmids in the alimentary tract. This species is not limited to 
fresh water, but has been taken on pools of salt water also. 
S. aquaticus is a common species in most parts of Europe, and is common 
also in many parts of the United States. 
Fourteen specimens, from the surface of ponds, Bernard harl)our. Northwest 
Territories, May 25. 1916, July 9, 1915. F. Johansen. 
REFERENCES. 
Absolon, K. 1900. Studie o jeskynnioh .siipiiiuskach. Vestnik Klubu jirirodov. Prostcjove, 
vol. 3, pp. 1-39. 
1901. Ueber Neaniira ienehrarum n. sp. aus den Hohlen des miihrischen Kar-stes; liber 
die Gattung Tetrodontophora Reuter und einige Sinnesorgane der Collembolen. 
Zool. Anz., vol. 24, pp. 57.5-586. 
Agron, H. 1903. Zur Kenntnis.s der Apterygoten-Fauna Slid-Scliweden.s. Stett. ent. Zeit., 
vol. 64, pp. 113-176. 
1904. LapplJindische Collembola. Arkiv Zool. K. Svenska Vetensk., vol. 2, pp. 1-30. 
Axelson, W. M. 1900. Vorliiufige jVIittheilinig iil)er einige neue Collembolen-Formen aus 
Finnland. Medd. Soc. Fauna Flora Fennica, vol. 26, pp. 105-123. 
1903. Beitriige zur Kenntniss der Collonibolen-Fauna Sibiriens. Ofv. Finska Vet.-Soe. 
Forh., vol. 45. pj). 1-13. 
1904. Verzeichniss einiger bei Golaa, im sudostlichen Norwegen eingesammelten Collem- 
bolen. Ent. Tid.skr., vol. 25, pp. 65-S4. 
1905a. Zur Kenntniss der Apterygotenfauna von Tvarniinne. Fests. Palmen, No. 15, 
pp. 1-46. 
1905b. Einige neue Collembolen aus Finnland. Zool. Anz., vol. 2cS, pp. 788-794. 
1906. Beitrag zur Kenntnis der CoUembolenfauna in der l^mgebung Revals. .\cta Soe. 
Fauna Flora Fennica, vol. 28, No. 2, pp. 1-22. 
