Collembolii 1 ,-, v 



The preceding description is based upon numerous specimens of typical 

 L. cyaneus from Europe and the United States. 



Packard's L. metallicus is this species, as I have found by a study of his 

 cotypes in the Museum of Comparative Zoology, ( lambridge, Mass. >" 



The specimens of this species collected by 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 antenna! segments are yellow; 

 and most of the denuded specimens are olivaceous, the effecl 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 S, figs. 67-72. 



Smynthurus aquaticus Bourlet, 1843. — Lubbock, 1873. — Oudenmns, L887 — 

 Uzel, 1890. 



Sminthurus apicalis Reuter, 1880. — Levander, 1894. 



Smynthurus apicalis Uzel, 1890. 



Sminthurus aquaticus Reuter, 1891, 1895. — Schott, 1894. — Lie-Pettersen 

 1896, 1898.— Schaffer, 1896.— Poppe and Schaffer, 1897.— Scherbakov, L898a 3 

 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-Pet terpen, 1907.— (Axelson) l.innan- 

 iemi, 1907, 1909, 1911, 1912.— Collinge, 1910.— Collinge and Shoebotham, L9I0. 



General colour yellow, brownish yellow, greenish, rose, or violet. Eye- 

 spots large, black. Eyes 8 + 8, two in each group being smaller than i he 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 firsl 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 t he claw proper, and extend- 

 ing often a little beyond the unguis. Ungues of third feel 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, un toothed, 

 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 mucrones. Mucrones convergent, spoon-like in 

 general form (figs. 70,71) elliptical from above, with stout pigmented midrib, 

 and three colourless lamella" as follows: (I) 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 



