NO. 2037. NORTH AMERICAN SPRING-TAILS— FOLSOM. 467 



Lovfdsh; the other segments purpUsh. Unguis (pi. 41, fig. 12) long, 

 slender, shghtly curved, five to seven toothed; unguiculus unidenr 

 tate. Dental spines (pi. 41, fig. 13) tridentate, commonly nine to 

 fifteen in large specimens, rarely as many as twenty; formula usually 

 4-6/2-5, 1, 1-2, 1. Intermediate teeth of mucrones five to eight, 

 as a rule, sometimes nine or ten. Length, 4 mm. 



Variation. — North American specimens agree with the six European 

 examples that I received from Doctor Schaffer. The unguis is 

 usually six-toothed, but may be five-toothed through the' absence of 

 the distal tooth; and some of the largest specimens may have seven 

 teeth, owing to the addition of a small tooth at the distal end of the 

 series. The number of dental spines in one large specimen that I 

 have from the State of Washington is as many as twenty, with the 

 formula 8/8, 1, 2, 1 (pi, 41, fig. 14), and the spines fall into two longi- 

 tudinal series — a variation mentioned by Linnaniemi ('12). Rarely 

 a spine bears a small fourth tooth. 



Distribution. — T. minor occurs in almost all parts of Europe. My 

 North American specimens are from few but widely separated 

 localities. 



Massachusetts. — Cambridge, January 26, February 2, 9, 18, 23, 25, 

 March 1, 8. 



V/ashington. — L. Bremner. 



Canada. — Toronto, Ontario, June 26, R. J. Crew. 



All the Massachusetts specimens were collected by me in a green- 

 house, and I was unable to find the species out of doors, even in the 

 immediate vicinity of the greenhouse mentioned. In regard to the 

 habitat of the specimens from the State of Washington and from 

 Canada, I have no data. 



CAVERNICOLOUS SPECIES OF TOMOCERUS. 



Packard ('77, p. 159) described as follows a white variety of Tomo- 

 cerus from a cave in Utah : 



Tomocerus plumbea (Linn.) var. alba. — Several specimens of a pale variety of this 

 species of "spring-tail" occurred, some of which were pure white, thoroughly bleached 

 out, while others were more or less dusky. Several of the larger specimens were pale, 

 with traces of dark markings on the body; the antennae, legs, and "spring" were 

 white, much paler than the body. In such examples the antennae are whitish, with 

 the two basal joints tinged with brown, the flagellum white, with a sUght purplish 

 tinge. Legs and spring almost pm-e white. Eyes black and well developed. Speci- 

 mens one-half or two-thirds grown are pure white, except the small, black eyes, which 

 are connected by a double black line; while other specimens, fully grown, are per- 

 fectly white. 



Similar individuals occurred in the Carter Caves of eastern Kentucky, and still 

 others occurred which were much darker than the Utah ones, forming a series con- 

 necting the extreme white variety, alba, with the ordinary plumbeous form, which 

 latter is found in the United States east of the Mississippi, Greenland, and Europe. 



