SEASONAL DISTRIBUTION OF NAJADICOLA 
INGENS (K.) (AC ARINA) IN A 
NEW HAMPSHIRE POND 
Arthur G. Humes and Henry D. Russell 
Department of Biology, Boston University 
Certain aspects of the geographical distribution and 
host relationships of Najadicola ingens (Koenike), a water- 
mite parasitic in fresh-water clams, have been investigated 
(Humes and Jamnback, 1950), but its seasonal distribution 
has not been reported. Wash Pond, Hampstead, New 
Hampshire, was selected for a study of the seasonal inci- 
dence and distribution of the mite. This pond was particu- 
larly suitable because of the high percentage of clams 
known to be parasitized there. 1 During the 13 months from 
December, 1949, to December, 1950, inclusive, a total of 
2211 clams, representing three species, was examined for 
mites. Collections were made monthly, as nearly as possible 
to the 15th, but in no case earlier than the 14th or later 
than the 19th day. All clams were collected in 6-30 inches 
of water from a strip of sandy shore about 500 feet in 
length at the west end of the pond near an outlet brook. 
The three species of clams found and the number of each 
examined were: Anodonta cataracta Say, 1147 specimens, 
Elliptio complanatus Solander, 1038, and Lampsilis radiata 
(Gmelin), 26. The size of each monthly collection and the 
number of each clam species contained therein (Table 1) 
varied, because of difficulties in collection, caused by ice, 
wind, and burrowing of the clams in winter. When possible 
at least 100 individuals of each clam species were collected. 
Data concerning A. cataracta for February and March had 
1 Humes, A. G., and H. A. Jamnback. 1950. Najadicola ingens 
(Koenike), a water-mite parasitic in fresh-water clams. Psyche, 
57(3) : 77-87. 
Ill 
