COLLEMBOLA OF THE FAMILY ISOTOMIDAE 97 



This common corticolous species may be found in large colonies 

 under the recently loosened bark of logs or stumps of many kinds of 

 trees, and occurs sporadically in humus under logs or other objects. 



Distribution. — In Europe, I. albella has been recorded from Nor- 

 way, Sweden, Finland, Estonia, Poland, and Germany. 



Maine: Orono, October, F. L. Harvey. 



Massachusetts: Arlington, April 13. 



New York: Albany, February 16, J. H. Blatner (New York State Museum). 

 Geneva, July 17, H. Glasgow. Ithaca, September 20, A. D. MacGUlivray 

 (Cornell University). Potsdam, May 23, D. B. Young (New York State 

 Museum) . Wells, July 21, D. B. Young (New York State Museum) . 



Illinois: Alto Pass, March 4, T. H. Prison and H. H. Ross (Illinois State Natural 

 History Survey). Bloomington, March 24, T. H. Prison and H. H. Ross 

 (Illinois State Natural History Survey). Homer, April 5, August 30. 

 Makanda, March 5, T. H. Prison and H. H. Ross (Illinois State Natural 

 History Survey). Mermet, March 8, T. H. Prison and H. H. Ross (Illinois 

 State Natural History Survey). Monmouth, April 2, T. H. Prison and 

 H. H. Ross (Illinois State Natural History Survey). Oakwood, April 20, 

 T. H. Prison (Illinois State Natural History Survey). 



Tennessee: Knoxville, April 5, H. E. Summers. 



Canada: Arnprior, Ontario, April 25, C. Macnamara. 



ISOTOMA (ISOTOMA) ALBELLA Packard variety LEONINA Packard 



fisotoma walkerii Packard, 1871, p. 16; 1873, p. 34. — MacGillivray, 1891, 



p. 274; 1896, p. 54. 

 Isotoma leonina Packard, 1873, p. 32. — MacGillivray, 1891, p. 273. — Guthrie, 



1903, p. 67. 



Description. — Dull greenish, snuff yellow, or tawny-yellow. Ap- 

 pendages white or pale yellowish. Head sometimes with fine blackish 

 dorsal mottlings. Young individuals are almost white. 



Remarks. — Except in coloration, leonina is exactly like albella. 

 Yoimg white individuals in colonies of leonina are indistinguishable 

 from those in colonies of albella. 



This is possibly the form that Packard described as walkerii, but 

 his description is insufficient, and the types of walkerii are lost, 

 whereas those of leonina are preserved in the Museum of Comparative 

 Zoology, Cambridge, Mass., where I had an opportimity to study 

 them; leonina is here made a variety of albella because the latter 

 name has page precedence (Packard, 1873). 



This abundant variety occurs, like typical albella, in large colonies 

 under the loose damp bark of trees, stumps, and logs of apple, oak, 

 maple, elm, pine, cypress, and doubtless other trees. It appears as 

 soon as the inner bark has begun to loosen from the sapwood, before 

 much decay has occurred. Packard's specimens of his walkerii 

 were taken on April 25, under the bark of an apple tree, where the 

 eggs hatched until May 6; the form being abundant in spring and 

 autmnn and in the following spring under the bark of the same tree. 

 In association with albella and its variety leonina under bark, Isotoma 



