COLLEMBOLA OF THE FAMILY ISOTOMIDAE 119 



apically, finely crenulate dorsally. Mucro (pi. 39, fig. 461) bidentate; 

 apical tooth slender, almost straight; second tooth dorsal, shghtly 

 hooked. General clothing of sparse short setae. Length, 1 mm. 



Remarks.— -This is not Guthrie's bidenticula, which is synonymous 

 with elongata MacGillivray. The present incomplete description is 

 based on that given by Miss Bacon, and the figures have been copied 

 from her original article. There should be no great difficulty in 

 recognizing this species, with its peculiar claws and mucrones and 

 its littoral habitat. 



Distribution. — Recorded as follows: 



California: Laguna Beach, in great numbers under stones between tide marks, 

 G. A. Bacon. 



