COLLEMBOLA OF MINNESOTA 65 



has the antennae comparatively longer and slenderer, though the 

 proportions between the segments are about as in I. minima, 

 III being little shorter than II, which is nearly twice as long 

 as I ; I and III together about equal IV. The claws are straighter 

 and rather more slender than in I. quadrioculata. 



This species is well distributed, though seldom very numer- 

 ous ; under bark, sticks and stones, under flower pots in the 

 green-house, almost anywhere where there is darkness and moist 

 mud, it may be sought. I have once taken it among the gills 

 of mushrooms. Not infrequently it lives with other white col- 

 lembolans such as Aphorura ambulans and Cyphodeirus albinus, 

 and the unaided eye can hardly distinguish the difference be- 

 tween the three species. 



Isotoma quadrioculata Tullb. 

 PI. X, Figs. 7, 8. 



1871. Isotoma quadrioculata. Tullberg, Fort, 6'fver Sv. Podur. p. 152. 



1872. Isotoma quadrioculata. Tullberg, Sver. Podur. p. 48. PL IX, 25-31. 

 1876. Isotoma quadrioculata. Tullberg, Coll. Borealia, p. 36. 



1890. Isotoma quadrioculata. Uzel, Thys. Bohemias, p. 66. 



1893. Isotoma quadrioculata. Schott, Palasarct. Coll. p. 74. , 



1895. Isotoma quadrioculata. Renter, Finl. Coll. p. 28. 



1896. Isotoma quadrioculata. Sckaffer, Coll. v. Hamburg, p. 183. PI III, 



71- 



1896. Isotoma quadrioculata. Lie-Pettersen, Norges Coll. p. 18. 



1897. Isotoma quadrioculata. Poppe & Schaffer, Coll. v. Bremen, p. 268. 



Tullberg's description is : "Third abdominal segment 

 shorter than the fourth, into which the furcula is inserted. 

 Ocelli 4, 2 on each side of the head. Dentes not longer than 

 the manubrium, straight ; mucrones bidenticulate. Length, 



mm." 



This has the shortest furcula of any species we have seen, 

 the dentes and mucrones together do not equal the manubrium. 

 There is one long hair at the base of the dentes as in I. bidentata. 

 No clavate hairs are borne by the tibiae. The claws are unarmed. 



Tullberg gives the color as -gray-blue. One of our spec- 

 imens, measuring i mm. in length, answers well to the descrip- 

 tion in all but size. It is gray-blue, with furcula and ends of legs 

 lighter or colorless. The others are entirely white with the ex- 

 ception of the eye spots, and they measure but .75 mm. The 



