90 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



Legs white, more or less pigmented basally. Furcula white, sUghtly 

 pigmented basally. Head relatively large ; front sharply demarcated 

 anteriorly, forming a blunt obtuse angle projecting between the 

 antennae, and broadly bordered with purple. Eye spots situated 

 close to the bases of the antennae. Eyes (pi. 29, fig. 324) eight on 

 each side, equal. Postantennal organ (pi. 29, fig. 324) close to eyes, 

 oval, shghtly longer than the diameter of an eye (as 9:8). Antennae 

 a little shorter than the head, with segments in relative lengths about 

 as 2:5:5:12; first three segments gradually expanding distally; fourth 

 elliptical. The antennae are inserted in foveae under the projecting 

 front, and their segments are strongly telescopic. Sense organ of 

 third antennal segment (pi. 29, fig. 325) with two linear, feebly curving 

 rods, subtended by a chitinous ridge. Special olfactory setae of 

 fourth antennal segment apparently absent. The mesonotum con- 

 ceals the pronotum. Abdominal segments without ankylosis. Fourth 

 abdominal segment longer than the third (as 5:4). The anal segment 

 terminates in three conspicuous sub triangular lobes: a suranal valve 

 and a pair of subanal valves. Tibiotarsus without a distal sub- 

 segment. Unguis (pi. 29, fig. 326) stout, feebly curving, untoothed. 

 Unguiculus extending two-thirds as far as unguis on the hind feet, 

 broadly lanceolate, acuminate, untoothed. Tenent hairs absent. 

 Furcula appended to the fifth abdominal segment, extending con- 

 siderably beyond the ventral tube. Manubrium with many ventral 

 setae, of which twelve are subapical in position. Dentes twice as 

 long as manubrium, slender, tapering, strongly crenulate dorsally, 

 densely setigerous. Mucro minute, slightly shorter than hind 

 unguiculus, tridentate (pi. 29, figs. 327-330); apical tooth long, acute, 

 upcurving; second tooth, small, conical, suberect or inclined back- 

 ward; third tooth long, thornlike, proximolateral, directed obHquely 

 backward. Dens with a long subapical ventral seta, which may 

 extend beyond the apex of the mucro. Rami of tenaculum quadri- 

 dentate; corpus with three (occasionally as many as five or six) setae. 

 General clothing of dense short stifl" unequal simple setae. Long erect 

 sensory setae absent. Integument smooth. Length, 0.8 mm. 



Remarks. — This species is to be added to the list of those collem- 

 bolans that, under certain favorable conditions, occur in masses of 

 countless numbers. I received from Prof. G. H. French hundreds of 

 thousands of individuals, taken in cornrows in a garden at Marissa, 

 111., by Thomas Key worth, who wrote that they were in clusters by 

 the millions; in fact, could be taken up by the shovelful on the ground. 

 This is especially remarkable because the specimens averaged onl}^ 

 half a millimeter in length, and a large proportion of them were almost 

 invisible to the naked eye. 



From Prof. P. S. Welch I received also an immense number of 

 specimens taken at Kiowa, Kans., by J. M. Miller, who stated: 



