90 COLLEMBOLA OF MINNESOTA 



Agaricus, hundreds on one plant, Brunswick, Maine. Salem 

 (Mass.), under a heap of horse manure, Aug. 15." 



It is difficult to point out the differences between this spe- 

 cies and that which I have identified as A. longispinus Tullb. 

 In figuring the antennae, the claws or the anal spines, one figure 

 would answer for either, though I doubt if A. boletivorus has 

 any tenent hair. The tenent hair is so slightly clavate on A. 

 Longispinus as to be scarcely noticeable. It appears, however, 

 that A. boletivorus is rather the thicker bodied of the two species, 

 and it is slightly smaller and far lighter in color. My specimens 

 reach one and one-third millimeters in length. Have taken them 

 often and in large numbers among the gills of mushrooms of 

 various kinds, and in tunnels which they had evidently bored 

 in the flesh of the caps. Several hundreds have been taken 

 from a single agaric. When the cap is broken up, and their hid- 

 ing places brought to light, they leap out and usually make a 

 bee-line for some overhanging fragment of mushroom, or other 

 place of shelter. They are very lively, usually running about half 

 an inch, then jumping nearly an inch, then alternating again. 

 The larger specimens can jump two inches when disturbed, but 

 when forced to take their largest leap they overdo themselves 

 and usually turn around, or turn a summersault in the air. so 

 that they alight 'tail end to," and begin running toward their 

 starting point., Usually under normal conditions they alight on 

 their feet, but when hurried will occasionally come down on 

 their backs. They prefer mushrooms which are beginning to 

 get stale and decay. 



Achorutes longispinus Tullb. 

 PI. X, Figs. 15-16; XI, Fig. 5. 



1876. Achorutes longispinus. Tullberg, Coll. Borealia. p. 37. PI. X, 31-34. 

 1896. Achorutes longispinus. Schaffer, Coll. v. Hamburg, p. 171. PI. IT, 



45- 



"Upper claw present. Mucrones of the furcula thick, con- 

 vergent. Anal spines large, about as long as the upper claw; 

 papillae separated at their bases. Length, 2 mm." Schaffer adds 

 "Keulenhaare der Tibien undeutlich" and "Der dunkelblaue Pig- 

 ment gleichmassig verteilt." 



