652 MOSQUITOES OF NORTH AMERICA 



the February larvae did not hibernate as such is abundantly proved by the almost 

 daily collections made during February, 1903, by the fact that larvae developed 

 in water with a portion of the mud bottom from woodland pools and, finally, 

 by the fact that I foimd the eggs in some samples of mud from the bottom of 

 breeding pools sent in to me for examination at my request. 



" The first find was made February 6th in a jar in which larvae of C. melor 

 nurus were being bred. These larvae were collected February 3d, and at that 

 time no trace of small wrigglers was noted. One example found on the 6th 

 seemed as if it had just hatched, and there is no reasonable doubt that the trans- 

 fer from the breeding pools to the house temperature induced development. 

 Collections were made in the field February 8th in a sleet storm, the pools ice 

 covered and the water temperature 36 degrees. Twenty-five specimens, all of 

 them apparently just out of the egg, were collected, and these mostly out of the 

 bottom mud where they seemed to be in hiding. To test this yet further, a 

 supply of bottom material was secured February 9th, and in less than twenty- 

 four hours minute larvae were found in each of the breeding jars into which it 

 was placed. It is positively proved, therefore, that during the early days of Feb- 

 ruary, in water just above the freezing temperature, the larvae of canadensis 

 may and do hatch from the egg under entirely natural conditions. Hatching 

 may be hastened by disturbing tiie material in which the eggs are laid, and this 

 probably accounts for the larvae first found in the jars. 



"February, 1903, was a cold month and the breeding pools in which the 

 larvae were foimd became iced over several times, so as to bar absolutely all 

 access to the surface ; nevertheless, there was no apparent decrease in the number 

 of specimens, but, on the contrary, a continuous increase. Artificial tests were 

 made February 18th and 19th, when the bottles with baby larvse were allowed to 

 freeze almost solid. Nevertheless they survived the test and specimens could be 

 watched partly imbedded in ice, wriggling to free themselves until the sur- 

 rounding temperature rose sufficiently to release the ice grip. In nature the 

 larvae usually manage to escape actual freezing by getting into the bottom mud, 

 and that was illustrated by an examination made March 2d, after a night when 

 the thermometer registered 23 degrees. The pool was completely ice-covered, a 

 hole was chopped near the edge with an ax, and through this hole larvae were 

 dipped up in fair numbers with the bottom material. No larvae were imbedded 

 in the ice. 



" Development at this season is slow and the new hatchings during early 

 March rapidly overhauled those that appeared earlier, so that by the middle of 

 that month the great bulk of the brood was about half grown or a little larger. 

 The pupal period ranges from two to seven days, according to temperature. 



" The earliest record for adults taken outdoors is April 14th and is also from 

 Mr. Brakeley. It is not until the early days of May, however, that both sexes 

 are at all abundant, and at that time not all of the hibernated eggs are yet 

 hatched. There is a false appearance of a second brood coming immediately 

 after the first adults are on the wing; but it seems fairly certain that all the 

 canadensis that are found until the middle of June are from hibernating eggs. 

 After that time the species decreases in number, though it has been taken in all 

 stages throughout the summer. What seems to be the second brood begins to 

 hatch during the early days of June, and thereafter I have not been able to 

 identify any definite period when young were present in large numbers. 



" Our records show larvae, pupae and adults at South Orange as early as April 

 27th, and at Garret Mountain, Paterson, April 29th. A month later. May 28th, 

 South Orange again had recently hatched larvae in considerable number. From 

 the Paterson district larvae were taken that matured early in September, and 

 larvae found in the Great Piece meadows in early September yielded canadensis 



