28 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



dull grayish forms with the pigment distributed as in quadrioculata. 

 According to him the dentes vary in length from somewhat shorter 

 to somewhat longer than the manubrium. 



In two individuals taken in colonies of diplophthalma (Homer, 111., 

 March 31, April 13), the eyes were absent; no ocular pigment was 

 present, and I could distinguish no corneae. 



F. diplophthalma is almost exactly like quadrioculata, the essential 

 difference between the two species being in respect to the number 

 of eyes. If traces of posterior eyes were present, diplophthalma 

 should be regarded as a variety of quadrioculata; but neither Lin- 

 naniemi (1912, p. 114) nor I have seen any clear evidence of such 

 eyes. As further evidence of the distinctness of the two species 

 Linnaniemi observes that the olfactory setae of the fourth antennal 

 segment in diplophthalma (as many as eight of which may be present) 

 are clearly differentiated; while in quadrioculata they are difficult to 

 distinguish from ordinary setae. 



Though diplophthalma has been found in company with quadri- 

 oculata, it occurs also alone. In one locality where I have several 

 times taken diplophthalma in abundance, I have not been able to 

 find quadrioculata. 



F. diplophthalma is found on the ground under wood or dead 

 leaves and in moss. I have taken hundreds of specimens in Illinois 

 under damp logs and damp dead leaves in swampy places. 



Distribution. — European authors have reported the species from 

 Norway, Sweden, Finland, England, Russia, and Nova Zembla. 



Illinois: Homer, March 24, 31, April 6, 7, 13, May 3. 



Greenland: Saunders Island, June 15, M. C. Tanquary (American Museum 

 of Natural History), 



FOLSOMIA FIMETARIA (Linnaeus) 



Plate 7, Figures 68-79 



Podura fimctaria Linnaeus, 1758, p. 609. 



Isotoma alba Tullberg, 1871, p. 152. — von Dalla Torre, 1895, p. 9. 



Isotoma fimetaria Tullberg, 1872, p. 48; 1876, p. 37. — Uzel, 1890, p. 66.— 



MacGillivray, 1891, p. 273; 1896, p. 58.— Schott, 1894, p. 75; 1896a, p. 



184; 1902, p. 21.— Reuter, 1895, p. 28.— Lie-Pettersen, 1896, p. 18; 



1898, p. 13.— Meinert, 1898, p. 169.— Schaffer, 1896, p. 183; 1900a, p. 



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



1898b, p. 12; 1899a, p. 47; 1899b, p. 5.— Carl, 1899, p. 310.— Carpenter 



and Evans, 1899, p. 251.— Absolon, 1900a, p. 29.— Carpenter, 1900, p. 



274.— BoRNER, 1901a, p. 46; 1903, p. 171.— Evans, 1901b, p. 153; 1908, 



p. 197.— FoLSOM, 1902a, p. 92; 1902b, p. 364.— Krausbauer, 1902, p. 



68.— Agren, 1903, p. 143; 1904, p. 21.— Guthrie, 1903, p. 64.— Axelson, 



1906, p. 11. 

 Isotoma manubriata MacGillivray, 1896, p. 49. 



Isoloma fimentaria Wahlgren, 1900a, p. 356; 1906a, p. 223; 1906b, p. 255. 

 Folsomia Candida Willem, 1902b, p. 280. 

 Isotoma {Fohomia) fimetaria Borner, 1903, p. 171. — Axelson, 1905b, p. 29. 



