74 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



MacGillivray (1896) retained the name of tricolor, I found to be 

 palustris; the remaining five specimens, from Salem, Mass., being 

 viridis. 



I. aequalis MacGillivray is also palustris, as I have found from a 

 cotype given to me by MacGillivray. 



The form with three stripes is trifasciata Bourlet (1839) as Hand- 

 schin (1929) notes. 



/. palustris lives in moist places, and is especially abundant along 

 the edges of ponds and streams, frequenting the vegetation in prefer- 

 ence to the water, though it is quite at home on the surface of the 

 water, where it leaps vigorously and repeatedly. The species occurs 

 on the seashore also, under seaweed, driftwood, or stones, and is 

 sometimes found on the snow. 



In a collection of Collembola taken from tlie stomachs of young 

 trout at Ithaca, N. Y., by 11. J. Pack, I found 38 specimens of /. 

 palustris. This collection comprised more than 600 collembolans, 

 representing 9 species. Mr. Pack found that Collembola formed 

 from 20 to 25 percent of the bulk of the stomach contents of the young 

 trout, which were mostly 25 to 30 mm in lengtli. 



This is one of the dominant species of its order. It is cosmopolitan 

 in distribution, everywhere common, and highly variable in colora- 

 tion, several varieties having received names. 



Distribution. — The typical form of I. palustris is known from all 

 parts of Europe, from Siberia, Nova Zembia, Spitsbergen, Bear 

 Island, Greenland, Ellesmere Land, Azores Islands, Sicily, Sardinia, 

 Algeria, Mesopotamia, Bismarck Archipelago, Argentina, Costa Kica, 

 and Mexico. 



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



Massachusetts: Arlington, January 16, March 10, April 6, 8, 13, May 2, 14, 



July 6, 10, August 2, November 6. Belmont, October 23. Cambridge, 



February 9, March 1, April 22, 29, 30, May 14, December 9. Lexington, 



April 17, May 7, 10, 16. Norwood, August 26. Waverley, March 27, 



April 4, 19, 21. Winchester, April 15. 

 New York: Ithaca, May, June, October, R. M. Hughes (Cornell University); 



May, June, H. J. Pack (Cornell University). Lakeville, October 7, E. A. 



Maynard. Pine Plains, June 14, D. B. Young (New York State Museum). 



Riverhead, Long Island, May 25, S. C. Bishop (New York State Museum). 



Rochester, March 11, E. A. Maynard. Sodus Point, June 29, J. D. Hood. 



Voorheesville, August 30, M. D. Leonard (New York State Museum). 

 Ohio: Salem, March 21, A. D. MacGillivray. Yellow Springs, February 9, 



March 4, April 3, August 28. 

 Indiana: La Fayette, J. J. Davis. 

 Illinois: Anna, May 6, 7, T. H. Prison (Illinois State Natural History Survey). 



Homer, April 5, 6, 9, 11, 16, 17, 24, 30, May 1, 5, 6, 9, June 9, 10, 11, 16. 



Urbana, January, C. A. Hart (Illinois State Natural History Survey) ; April 



30. Volo, Aprii 4, T. H. Frison and H. H. Ross (Illinois State Natural 



History Survey). 



