104 



allied to H. viridis, but much more extensible. Found in the 

 eastern part of Massachusetts, probably in other parts of the East- 

 ern States. • 



2. H. carnea.) Agass. Larger than the gracilis^ of a light 

 reddish brown color, allied to H.fusca, but having the tentacula 

 shorter. Found in Massachusetts and Connecticut very abund- 

 antly ; much more common than the last. 



3. H. tenuis, Ayres. About the size of the carnea, which it 

 resembles in color, and to which it is allied, but from which it 

 differs in the same point and to about the same degree as carnea 

 differs i^romfusca ; the tentacula are much less developed, hav- 

 ing not more than about half the size of those of carnea. In micro- 

 scopic structure it resembles carnea as closely as that does^wsca. 

 It is found very abundantly near San Francisco, Cal. 



Whether we shall yet detect, on the Pacific side of the moun- 

 tains, a green species to represent H. gracilis, or perhaps others 

 entirely distinct, is left for future research. 



Dr. Durkee exhibited, under the microscope, the rostrum 

 or sting of the common Mosquito, (Culex pipiens.) 



Dr. Durkee remarked that one of the most remarkable features 

 in the anatomy of the mosquito is, that the parts which consti- 

 tute the mouth are elongated so as to form a beak extendino; hori- 

 zontally like that of some birds. The beak or sting is about 

 half the length of the body, and to the unassisted eye appears to 

 be very simple in its structure. When examined with the micro- 

 scope, however, it is found to be composed of seven different 

 parts, which are comparatively stout on one edge. These parts 

 vary in length, and can be separated from each other without 

 much difficulty. They are broad at the upper part, where they 

 are united to the head, and they gradually taper to a point. One 

 of the parts is a tubular canal or groove, in which the others are 

 lodged when the proboscis is not in use. Dr. Durkee stated that 

 he had not been able to find any appearance of teeth, except on 

 the two longest pieces ; in these he had found them near the tip. 

 The two longest pieces, also, are marked by transverse lines, 

 extending from one edge to the other, throughout their whole 

 length. 



