70 COLLEMBOLA OF MINNESOTA 



Isotoma caeruleatra n. sp. 

 PI. IX, Figs. 11-14. 



Dark clear blue, nearly black. Legs yellow, excepting 

 coxae and basal part of trochanters, which are dark blue. An- 

 tennas entirely blue, slightly lighter at proximal end of Ant. I. 

 Manubrium blue, the same color extending onto the dentes 

 very slightly. Dentes yellow, growing paler toward distal end 

 Head broad, blue, marked dorsally with yellow. Body narrow, 

 short-haired except for a few longer hairs on the two last abdom- 

 inal segments. Abd. II, III and IV about equal in length. Ant. 

 II equal to III, Ant. IV about twice as long as III, I very small. 

 Superior claw with two small teeth set on opposite edges and so 

 placed that one covers the other when the claw is seen in profile. 

 They show well when one views the claw from below. Inferior 

 claw with one small inner tooth situated on the most prominent 

 part of the inner hump. The inferior claw r seems to bend away 

 from the superior one, particularly in the third pair (the figure 

 is from the second pair), making the hump appear the more 

 prominent. No tenent hairs present. 



Manubrium about half as long as dentes and mucrones to- 

 gether. Dentes short and comparatively thick, arcuate, set dor- 

 sally with a row of stiff hairs, rather slender at distal end, 

 crenulate or dentate on lower margin, the proximal one-third 

 irregularly so. Mucrones four-toothed : the ante-apical tooth 

 long and slender, the two proximal teeth set nearly opposite 

 each other. Length, 2 mm. Taken but once, in Apr. 1894, by 

 Mr. O. W. Oestlund near Minneapolis. 



The species approaches very closely to I. grandiceps Renter. 

 but lacks the outer denticle on the superior claw, and possesses, 

 besides, the normal number of ocelli. I. grandiceps has but 

 seven to each eyespot. From I. hiemalis, to which it is even 

 more closely related, it differs in its much darker color, and 

 in the presence of teeth on the claws. 



Isotoma palustris Miiller. Forma principalis. 

 PI. IX. Figs. 8-10. 



1740. Podura aquatica cinerea. DeGeer, Act. Soc. Roy. Ups. 

 1776. Podura palustris. Miiller, Zool. Dan. Prodr. p. 184. 



