173 



Pselaphidae of the United States. The introduction was 

 read, containing tables exhibiting the analogies between the 

 American and European species of Coleoptera, and show- 

 ing the importance of a careful examination of the structure 

 of the antennae in forming the different subdivisions. 



Mr. Ayres made some remarks upon a species of Pike, 

 described by Dr. Richardson in his Fauna Boreali Ameri- 

 cana as the Esox lucius. 



This fish has been also described by Rev. Zadock Thompson, 

 under the name of Esox nohilior. In a pond near Bellows Falls 

 the Pike, having been artificially introduced, has passed from 

 thence into the still water at the foot of the Fall, where it is said 

 to grow to the size of twenty or thirty pounds. 



Mr. Ayres noticed this difference in the two species. In the 

 Esox lucius the side of the head is smooth, but in the Esox estor^ 

 there is a mark of scales on the anterior edge of the operculum. 



Mr. Ayres observed that the rivers of New England are this 

 year very low, and that there is a remarkable disease in the 

 fishes, which consists in the appearance of black spots scattered 

 over the entire surface of the fish. On the removal of the scale 

 the spot remains. It appears to be an ecchymosis in the fold of 

 skin which encloses the base of the scale. It sometimes covers 

 all the gill membranes. 



Dr. Storer inquired whether it was not a parasite. 



Mr. Ayres said that he had been told that it was, but he had 

 been unable to discover any parasite. He had often seen para- 

 sites in fresh-water fishes, and once in a salt-water fish. But the 

 spots referred to have a totally different appearance. 



Mr. Ayres added, that this disease in the fishes finally destroys 

 the rays of the fins by cutting them off at the joints, so that the 

 tail-fins are reduced to little stumps. This .effect is also some- 

 times produced by parasites. 



Dr. Burnett had examined some larvcE, received from Dr. 

 George Bartlett of Boston, which had been vomited by a gen- 

 tleman affected for several years with dyspepsia. Dr. Burnett 

 had compared the insects and found them nearly identical with 

 the Calliphora vomitoria, which lays large quantities of eggs in 

 putrid meat, the eggs being about a line in length and shaped 

 like a kernel of rye. 



