Animals of the Mississipjjt Bottoms near Quincy. 181 



Ocenis^ nymph (1). 



A small brown form with three long, fringed caudal ap- 

 pendages, and with the respiratory appendages on segments 

 1-5 of the abdomen; those on segments 3-5 concealed by the 

 plate-like pair of the second abdominal segment. First respira- 

 tory appendages small, erect, not concealed. Head without 

 conical tubercles. Antennae, legs, and caudal appendages white, 

 with brown annuli. 



A few examples were taken in Willow and Wood Sloughs. 

 Ccenis, nymph (2). 



A second small nymph, from Willow Slough, has three 

 prominent conical tubercles on the head which agree very 

 closely with those of the European species C. luduosa, as 

 figured in Mr. Eaton's monograph of this group of insects. 

 Our insect differs in having the prothorax narrowed towards 

 the front; and in certain other characters does not quite agree 

 with Mr. Eaton's description of the genus. 



ARACHNID A. (Spiders and Mites.) 



Tetragnatha graUatot\ Hentz. 



(Hentz, Bost. Jour. Nat. Hist., vi, 26, PI. iv, figs. 1 and 2.) 

 A small, slender-bodied, long-legged spider, large examples 

 of which are .50 inch in length. Extremely common about 

 the sloughs and lakes, often living over the water, exposed on 

 dead stems and branches. It was sometimes brought in by the 

 small seines in situations such that it seemed it must have been 

 in the water. Its food probably consists of small gnats. 



Arrenurus sp. 



A pale water mite with long ciliated legs was frequently 

 taken by surface nets in the deep water of the bay. It is, I 

 believe, a river species. 



VERMES. (Worms.) 



This group is not of the same importance to fish culture 

 as are the crustaceans and insects — unless it be as parasites — 

 and we shall not give those observed at Quincy more than a 

 passing notice. 



