COLLEMBOLA OF THE FAMILY ISOTOMIDAE 51 



sally, but sepcarated by a suture ventrolaterally. Tibio tarsus with a 

 distal subsegment. Unguis (pi. 19, fig. 192) slender, without lateral 

 or inner teeth. Unguiculus extending half as far as the unguis on the 

 second and third pairs of feet; shorter on the first pair; lanceolate, 

 acuminate, untoothed, with a pair of inner lamellae. Tenent hairs 

 one or two; often 1, 2, 2. Furcula appended to the fifth abdominal 

 segment, long, extending to the ventral tube. Manubrium a little 

 longer than dentes, with many short dorsal setae and a pair of ventral 

 subapical setae. Dentes stout, with about 20 coarse, somewhat 

 irregular, transverse, dorsal folds, except on the proximal third; with 

 many ventral setae and fewer dorsal setae. Mucro short, tridentate 

 (pi. 19, figs. 193-196); first and second teeth subequal, in longitudinal 

 ahnement; tliird tooth lateral; apical tooth almost straight or shghtly 

 hooked; anteapical tooth suberect or shghtly inclined; third tooth 

 close to second and subequal to it, though somewhat variable in size; 

 outer and inner lamellae present. Rami of tenaculum quadridentate; 

 corpus with one stout curving ventral seta. Clothing (pi. 19, fig. 197) 

 of dense stifl' simple setae, becoming longer toward the end of the ab- 

 domen; erect sensory setae apparently absent. Integument smooth, 

 not reticulate. Maximum length, 1.4 mm. 



Remarks. — The writer has redescribed this species from four co- 

 types and a large amount of type material received from Dr. MacGilli- 

 vray. It has been taken in immense numbers at Alameda, N. Mex., 

 by E. Van Patten. 



Type and co/?/pe.s.— U.S.N. M. no. 42986. 



PROISOTOMA (PROISOTOMA) MINUTA (Tullberg) 



Plate 19, Figures 198-207 



Isotoma minuta Tullberg, 1S71, p. 152; 1872, p. 47; 1876, p. 36. — Schott, 

 1894, p. 74; 1902, p. 21.— von Dalla Torre, 1895, p. 10.— Schaffer, 1896, 

 p. 183; 1900a, p. 248; 1900b, p. 255.— Scherbakov, 1898a, p. 59; 1898b, 

 p. 11.— AxELSON, 1900, p. 113; 1905b, p. 29; 1900, p. 13.— Borner, 1901a, 

 p. 45; 1903, p. 171.— Kratjsbatjer, 1902, p. 41.— Wahlgren, 1906b, p. 

 254.— Evans, 1908, p. 197. 



Isotoma clavipila Axelson, 1903a, p. 7. 



Proisotoma minuta Linnaniemi (Axelson), 1907, p. 21; 1911, p. 14; 1912, p. 

 130.— Bagnall, 1909, p. 501.— Stach, 1922a, p. 17.— Womersley, 1924a, 

 p. 32; 1925, p. 219.— Handschin, 1929, p. 61. 



Description. — Grayish or bluish; largest individuals heavily pig- 

 mented with blue, interspersed with pale spots; specimens of medium 

 size bluish gray, with scattered mottled blue pigment and with 

 intersegmental white bands; small individuals white. Eye spots 

 black. Eyes (pi. 19, fig. 198) eight on each side, equal. Postantennal 

 organ (pi. 19, fig. 198) near the eyes, elliptical to ovate-elliptical, 

 two and one-half to three times as long as the diameter of an eye. 

 Antennae a little longer than the head; segments in relative lengths 

 about as 4:5:5:12. Sense organ of third antennal segment (pi. 19, fig. 



