Collembola 15 a 
The preceding description is based upon numerous specimens of typical 
L. cyaneus from Europe and the United States. 
Packard's L. metaUicus is this species, as I have found by a study of his 
cotypes in the Museum of Comparative Zoology, Cambridge, Mass. 
The specimens of this species collected b}^ the Expedition are all typical as 
regards structural details, but most of them are atypical in respect to colouration. 
Thus, in a heavily pigmented specimen, all four antennal segments are yellow; 
and most of the denuded specimens are olivaceous, the effect of the yellow 
ground colour in combination with minute spots of violet pigment. 
L. cyaneus is primarily a species of the humus, but occurs also in other 
situations, as under loose dead bark or in moss. The species is common under 
sticks or stones on the ground, and is often found on soil that is too dry for the 
existence of collembolans without scales. 
Lepidocyrtus cyaneus has been reported from northern Siberia, Greenland, 
most parts of Europe, the United States, Africa (Egypt, Kamerun, German 
East Africa) and the Bismarck archipelago. 
Nine specimens, under driftwood on higher, dry tundra, Demarcation 
point, Alaska, May 16, 1914. F. Johansen. 
Sminthurides aquaticus (Bourlet). 
Plate 8, figs. 67-72. 
Smynthurus aquaticus Bourlet, 1843. — Lubbock, 1873. — Oudemans, 1887. — 
Uzel, 1890. 
Stninthurus apicalis Renter, 1880. — Levander, 1894. 
Smynthurus apicalis Uzel, 1890. 
Smitithurus aquaticus Eeuter, 1891, 1895. — Schott, 1894. — Lie-Pettersen, 
1896, 1898.— Schaffer, 1896.— Poppe and Schaffer, 1897.— Scherbakov, 1898a, 
1898b.— Carl, 1899.— Krausbauer, 1902.— Evans, 1908. 
Smynthurus amicus Folsom, 1896. 
Sminthurus (Sminthurides) aquaticus Borner, 1900. 
Prosminthurus aquaticus Willem, 1900. 
Sminthurides aquaticus Borner, 1901a, 1906.^ — Agren, 1903. — Axelson, 1904, 
1905a.— Wahlgren, 1906a.— 1906b.— Lie-Pettersen, 1907.— (Axelson) Linnan- 
iemi, 1907, 1909, 1911, 1912.— Collinge, 1910.— Collinge and Shoebotham, 1910. 
General colour yellow, brownish j^ellow, greenish, rose, or violet. Eye- 
spots large, black. Eyes 8 + 8, two in each group being smaller than the others 
(fig. 67). Antennae purple, slightly longer than the head, with fourth segment 
not subsegmented. Antennae of male with second and third segments modified 
to form clasping organs. Abdomen segmented dorsally. Unguis of first and 
second feet (fig. 68) slender, with inner margin unidentate a little beyond the 
middle; unguiculus extending two-thirds as far as the unguis, lanceolate, acute, 
with a subapical filament as long, to twice as long, as the claw proper, and extend- 
ing often a little beyond the unguis. LTngues of third feet (fig. 69) three-fourths 
as long as those of the other feet, slender, feebly curving, without teeth; ungui- 
culus extending not quite as far as the unguis, broadly lanceolate, untoothed, 
with apical filament exceeding the unguis. Tenent hairs absent. Third tibio- 
tarsi with a peculiar distal sense organ (fig. 69) consisting of a pair of slipper- 
shaped structures, with a stout seta extending beyond the tibio-tarsus. Ventral 
tube emitting a pair of short rounded sacs. Furcula reaching beyond the mouth. 
Dentes three times as long as niucrones. Mucrones convergent, spoon-like in 
general form (figs. 70,71) elliptical from above, with stout pigmented midrib, 
and, three colourless lamellse as follows: (1) inner dorsal, with radiating ribs 
terminating in marginal teeth; (2) outer dorsal, with faint radiating ribs due 
to dorsal ridges, but with entire margin; (3) ventral lamella, narrow and entire. 
Basal lateral mucronal seta present. Rami of tenaculum tridentate (fig. 72); 
