270 AGRICULTURAL EXPERIMENT STATION. 



February i8th and 19th, when the bottles with baby larvae 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 surrounding temperature 

 rose sufficiently to release the ice grip. In nature the larvas 

 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 fcxes 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 num- 

 ber, though it has been taken in all stages throughout the summer. 

 What seems tO' be tlie second brood begins to- hatch during the 

 early days of June, and thereafter I have not been able to iden- 

 tify 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 dis- 

 trict larvae were taken that matured early in September, and 

 larvae found in the Great Piece meadows in early September 

 yielded canadensis up tO' the 21st of that month. Perhaps the 

 greatest abundance of canadensis is in late May, and thereafter 

 a constant decrease. It occurs throughout the State. 



The egg is black, spindle-shaped, smooth, rather thicker than 

 that of sollicitans. When the top has been lifted ofif to admit the 

 egress of the larva, it looks like a stubby, half smoked cigar. 

 This egg may be laid either on the water, through which it sinks 

 to the bottom at the edge of a pool, or on the moist ground of 



