514 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.50. 



scnted externally by a minute rudiment. Antennae short. Mouth 

 parts biting; mandibles with a well developed molar surface. Body 

 short and stout. Ungues very long and slender. Unguiculi absent. 

 Furcula very long, extending beyond the ventral tube, clearly 

 attached to the fourth abdominal segment. Dentes very long, 

 strongly bowed, apically ringed, two-segmented. Mucroncs lamel- 

 late. Anal spines absent. Integument tuborculate. 



PODURA AQUATICA Linnaeus. 



Plate 25, figs. 246-250. 



Podura aquatica Linnaeus, 1758. — Nicolet, 1841. — Tullberg, 1871, 1872. — 

 Lubbock, 1868, 1873.— Packard, 1873.— Parona, 1879, 1882.— Dalla 

 Torre, 1888, 1895.— Uzel, 1890.— MacGillivray, 1891.— Schott, 1894, 

 1902.— Reuter, 1895.— Schapfer, 1896, 1900a, 19006.— Lie-Pettersen, 

 1897.— PoppE and Schapfer, 1897.— Scherbakov, 1898.— Carl, 1899, 

 1901.— Wahlgren, 18996, 1906a.— Carpenter and Evans, 1899.— Absolon, 

 1900a, 19015.— WiLLEM, 1900.— Borner, 1901f/.— Krausbauer, 1901.— 

 Agren, 1903.— Guthrie, 1903. — Axelson, 1906. — (Axelson) Linnaniemi, 

 1907, 1912. 



Hypogastrura aqmitica Bourlet, 1839. 



Hydropodura aquatica Borner, 1901c, 1902. 



Podura granulata MacGillivray, 18935. 



Blackish blue; anteimae a*nd legs reddish brown; furcula pale 

 brown. Eyes eight on each side (fig. 246). Ocular areas with coni- 

 cal elevations between the eyes. Antennae stout, cylindrical, 

 shorter than the head, with segments about as 4:5:6:7 in relative 

 lengths. Olfactory hairs of fourth antennal segment absent. Sense- 

 organ of tliird antennal segment consisting of a pair of short stiff 

 setae (fig. 247). A dorsal subsegment occurs on the anterior part of 

 each body segment except the ninth. Unguis (fig. 248) slender, 

 curving, longer than the tibiotarsus, unidentate behind the middle 

 of the mner margin. Unguiculus represented only by a toothlike 

 rudiment. Tenent hair single, unlviiobbed. Rami of tenaculum 

 quadridentate (fig. 249). Furcula extending as far as the first 

 pair of legs. Manubrium short. Dentes strongly bowed outward, 

 apically convergent, with an obsolete transverse suture two-fifths 

 from the base, and with the tubercles of the distal tliird arranged 

 in transverse rings. Mucrones (fig. 250) three-fifths as long as hind 

 ungues, ^vith outer and inner lameUae, and with a prominent dorso- 

 lateral rounded-triangular basal lobe. Aiial spines absent. Body 

 clo tiling of few minute curving setae; dens witli 12 to 17 long curving 

 dorsal setae, most of which are in two longitudinal series. Length, 

 1.3 mm. 



American specimens agree with 28 European examples which I 

 received from Dr. Caesar Schaffer, except in having stouter bodies 

 and appendages than the latter. 



