72 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



respectively; a narrow median ventral lamella is also present. Rami 

 of tenaculum quadrideatate ; corpus with many ventral setae. Gen- 

 eral clothing of dense short stiff simple setae of irregular length, 

 becoming slightly longer posteriorly ; with longer erect simple sensory 

 setae; spinulate setae (pi. 25, fig. 280) occur on the genital and anal 

 segments. Length, 1.7 mm. 



Cotypes.—U.S.'NM. no. 42998. 



Distribution. — Recorded as follows: 



New Mexico: Las Vegas Hot Springs, February 16, W. P. and T. D. A. Cockerell. 



ISOTOMURUS PALUSTRIS (Muller) 



Plate 25, Figure 281; Plate 26, Figures 284-290 



Podura palustris Muller, 1776, p. 184. — Gmelin, 1778-93, p. 2911. — Bourlet, 

 1841-42, p. 117. 



Isotoma palustris Lubbock, 1873, p. 169. — Reuter, 1876, p. 82 (part), 1890, p. 

 20; 1891, p. 228; 1895, p. 26.— Reuter, L. and 0. M., 1880, p. 207.— 

 ToMosvARY, 1882, p. 124.— Parona, 1S85, p. 45; 1895, p. 699. — von Dalla 

 Torre, 1888, p. 156; 1895, p. 10.— Uzel, 1890, p. 62; 1891, p. 920.— Parfitt 

 1891, pp. 342-343.— Schott, 1891b, p. 22; 1894, p. 63; 1896a, p. 184; 1902, p 

 22.— Lie-Pettersen, 1896, p. 17; 1898, p. 13; 1907, p. 65.— MacGillivray 

 1896, p. 48.— ScHAFFER, 1896, p. 186; 1898, p. 401; 1900a, p. 246; 1900b, p 

 256. — PoppE and Schaffer, 1897, p. 268. — Scherbakov, 1898a, p. 58 

 1898b, p. 7.— Carl, 1899, p. 311; 1901, p. 262.— Carpenter and Evans 

 1899, p. 247.— Absolon, 1900a, p. 30.— Borner, 1901a, p. 50; 1902a, p 

 105.— Evans, 1901b, p. 153.— Becker, 1902, p. 26.— Krausbauer, 1902 

 p. 40. — Agren, 1903, p. 132. — Guthrie, 1903, p. 70. — Philiptschenko 

 1905, p. 3.— Wahlgren, 1906b, p. 255; 1907a, p. 5.— Collinge, 1910, p 

 11. — Collinge and Shoebotham, 1910, p. 112. — Bacon, 1914, p. 153. — 

 Folsom, 1919a, p. 11. 



Isotoma tricolor Packard, 1873, p. 34 (part). — MacGillivray, 1891, p. 274 

 (part); 1896, p. 48. 



Isotoma aquatilis Lubbock, 1873, p. 170 (part). — Parona, 1879, p. 600; 1882, 

 p. 463. 



Isotoma stuxbergii Tullberg, 1876, p. 35 (part). 



Isotoma tullbergi Moniez, 1889, p. 28. 



Isotoma stuxbergi Moniez, 1891, p. 70. 



Isotoma aequalis MacGillivray, 1896, p. 49. 



Isotomurus palustris Borner, 1903, p. 171; 1906, p. 173. — Axelson, 1905b, 

 p. 35; 1906, p. 16.— Linnaniemi (Axelson), 1911, p. 19; 1912, p. 186.— 

 Imms, 1912, p. 93. — Shoebotham, 1917, p. 221. — Brown, 1918, p. 186; 



1926, p. 206.— Wahlgren, 1919, p. 751.— Denis, 1921, p. 126; 1922a, 

 p. Ill; 1924b, p. 232; 1927, p. 196.— Stach, 1922a, p. 23; 1922b, p. 117.— 

 Handschin, 1924a, p. 121; 1924b, p. 85; 1925a, p. 232; 1927, p. 110; 1928a, 

 p. 542; 1928b, p. 6; 192Sc, p. 129; 1929, p. 72.— Womersley, 1924a, p. 33, 



1927, p. 377. 



Description. — Very variable in coloration. The typical form (pi. 25, 

 fi,g. 281) is yellowish or greenish with blue, purple, or blackish pig- 

 ment; having a median dorsal stripe with irregular margins; and fre- 

 quently lateral spots, which may coalesce to form a stripe on each side 

 of the body. Head often with a dorsal lunate or anchor-shaped spot. 



