80 
Psyche 
[September 
Park’s Pond, Clifton; (40) Unity Pond, Unity; (41) China 
Lake, China. 
Quebec: (42)Massawippi Lake, at Ayer’s Cliff. 
New Brunswick: (43) Cranberry Lake, Harvey Station. 
Of the 14 species of clam hosts 3 were parasitized by N. ingens 
and 11 were negative. The 3 positive species were Elliptio complan- 
atus (Solander) (2054 specimens of which 231 or 11.2% were 
positive), Anodonta cataracta Say (625 specimens of which 242 or 
38.7% were positive), and Lampsilis radiata (Gmelin) (152 speci- 
mens of which 18 or 11.8% were positive). The negative species 
included 17 Ligumia nasuta (Say), 3 Lampsilis cariosa (Say), 3 
Lampsilis ventricosa (Barnes), 19 Lampsilis ochracea (Say), 79 
Anodonta implicata Say, 59 Anodonta marginata Say, 38 Alasmi- 
donta undulata (Say), 1 Alasmidonta heterodon (Lea), 25 Strophi- 
tus rugosus Swainson, 1 Leptodea fragilis Rafinesque, and 1 Prop- 
tera alata Say. 
The highest degree of parasitism in any single locality was 87.3% 
for Anodonta cataracta at Wash Pond, N.H., and 57% for Elliptio 
complanatus at Crystal Lake, N.H. 
Judging from the relative number of individual clams parasitized, 
the preferred host seems to be Anodonta cataracta , with 1 out of 
every 3 clams containing mites. Elliptio complanatus appears to 
be next in preference, with 1 out of every 9 parasitized. Lampsilis 
radiata seems least preferred of the three hosts. The high figure of 
11.8% is misleading, since it is based upon parasitized clams from 
only two localities. One, Massawippi Lake, Quebec, produced 18 
clams of which 16 were parasitized; the other, Lake Champlain at 
Sandbar State Forest Park, Vt., comprised 23 L. radiata of which 
only 2 contained mites. The remaining 134 L. radiata were negative. 
The samples of clams from the various localities were not of equal 
size. At several localities only a few clams were collected. Table I 
shows the number of clams of each of the 3 host species examined 
in the 43 localities. The numbers in parentheses indicate the number 
of individuals which were parasitized by N. ingens. The average 
number of clams examined of all 14 species in the 43 positive local- 
ities was 51 (1-253) and in the 31 negative localities 28 (3-134). 
Only 2 of the negative localities comprised more than 100 clams. 
Excluding these the average number of clams examined in 29 neg- 
ative localities becomes 21 (3-80). These data indicate the possibil- 
