COLLEMBOLA OF THE FAMILY ISOTOMIDAE 77 



apically; second and third dark apically or tliroughout; fourth dark. 

 Precoxal segments and coxae more or less pigmented; femora often 

 pigmented basally and apically; tibiotarsi dark blue; furcula unpig- 

 mented. Length, 2.3 mm. 



Small individuals have very little pigment. Individuals about 1.5 

 mm in length have the black antennal bases, the spot on the vertex, 

 and a little pigment at the bases of the legs; vt^hile the median dorsal 

 hne is represented by a series of black spots, and the subdorsal spots 

 are ill-defined. 



Remarks. — This variety resembles var. maculata SchafFer (1896), 

 examples of which I have received from him. The type of coloration 

 is, however, rather different in the two forms, as may be seen by 

 comparing my figures with those of Stach (1924, pi. 2, figs. 9-12). 

 The median dorsal stripe in texensis is not narrow, as it is in maculata, 

 but is always broad, with irregular margins. 



Cotypes.—V.S.l^^M. no. 42999. 



Distribution. — Recorded as follows: 



Texas: College Station, December 22, C. A. Hart. 



ISOTOMURUS PALUSTROIDES. new species 



Plate 26, Figures 291-295 



Description.. — Dark violet with white spots. Legs, manubrium, and 

 bases of dentes pale purple. Antennae purple; basal ring blackish 

 purple. Eyes (pi. 26, fig. 291) eight on each side, subequal. Postan- 

 tennal organ (pi. 26, figs. 291, 292) elliptical, slightly shorter than, 

 or subequal to, the diameter of an adjacent eye. Antennae one and 

 tluee-fourths times as long as the head, with segments in relative 

 lengths as 4:8:9:7.5. 



Abdominal segments without ankylosis. Third abdominal segment 

 longer than the fourth (as 4:3). Unguis (pi. 26, fig. 293) slender, curv- 

 ing, with a pair of minute lateral teeth and with inner margin untoothed. 

 Unguiculus sublanceolate, untoothed, apically setaceously prolonged, 

 extending two-thirds as far as tlie unguis. Tenent hairs absent, rep- 

 resented by a single long simple hair. On each mid and hind tibiotar- 

 sus (fore legs also?) there is a long hair, minutely fringed on all sides 

 (bothriotrix), inserted on the same side as the unguis (upper side), 

 and almost half as long as the tibiotarsus. Furcula attaining the 

 ventral tube. Dentes about twice as long as the manubrium. Mu- 

 crones (pi. 26, fig. 294) about as long as hind unguicuh, quadridentate, 

 in form essentially as in palustris. Apical tooth small but evident, 

 at base of second; second and third teeth dorsal, large, subequal, sub- 

 conical, in longitudinal alinement ; fourth tooth lateral, obhque, acute. 

 Basolateral mucronal seta probably present normally, as mdicated 

 by the insertion pit m plate 26, figure 294. General clothing of 

 abundant short tapering setae, fringed on all sides (pi. 26, fig. 295). 



95462—37 6 



