354 ANNUAL OF SCIENTIFIC DISCOVERY. 



ON THE STING OF THE MOSQUITO. 



At a recent meeting of the Boston Society of Natural History, Dr. Durkee 

 remarked that one of the most remarkable features in the anatomy of the 

 mosquito is, that the parts which constitute the mouth are elongated so as to 

 form a beak extending horizontally 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 microscope, 

 however, it is found to be composed of seven different parts, which are com- 

 paratively 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 

 trans verss lines, extending from one edge to the other, throughout their whole 

 length. 



ON THE ARTIFICIAL PROPAGATION OF SALMON NEAR PERTH, 



SCOTLAND. 



At the last meeting of the British Association, Mr. Edward Ashworth gave 

 an account of some interesting experiments made upon the river Tay, Scot- 

 land, in respect to the artificial propagation of salmon. The experiments 

 were made upon the estate of the Earl of Mansfield, by a company of gen- 

 tlemen associated for the purpose. A small stream flowing into a mill-pond 

 offered every facility for the equable flow of water through the boxes and 

 pond. Three hundred boxes were laid down in twenty-five parallel rows, 

 each box partly filled with clean gravel and pebbles, and protected at both 

 ends with zinc grating to exclude trout and insects. Filtering beds were 

 formed at the head and foot of the rows, and a pond for the reception of the 

 fry was constructed immediately below the hatching ground. On the 23d of 

 November, 1855, operations were commenced, and by the 23d of December 

 300,000 ova were deposited in the boxes. The fish were taken from spawn- 

 ing beds in the Tay. So soon as a pair of suitable fish were captured, the 

 ova of the female were immediately discharged into a tub one fourth full of 

 water, by a gentle pressure of the hand from the thorax downward. The 

 melt of the male was ejected in a similar manner, and the contents of the tub 

 stirred with the hand. After the lapse of a minute, the water was poured 

 off, with the exception of sufficient to keep the ova submerged, and fresh 

 water supplied in its place. This also was poured off and fresh substituted 

 previous to removing the impregnated spawn. The ova was placed in boxes 

 as nearly similar to what they would be under the ordinary course of natural 

 deposition as possible, with this important advantage : in the bed of the river, 

 the ova are liable to injury and destruction in a variety of ways. The allu- 



