2o6 AGRICULTURAL EXPERIMENT STATION. 



insects were tempted to lay eggs on the sides of the jar an incli 

 above the wet bottom. August 19th, the eggs in jar No. 8, were 

 covered with water, but no larvae hatched from this series. Some 

 of the eggs in jar 4, became covered with water September ist. 

 and hatched. September 5th, another lot was covered and also 

 hatched. Some of the eggs were covered with water soon after 

 they were laid and were kept covered until September 5th when, 

 no larvae having hatched, the water was poured off and they were 

 allowed to dry. September 23d, when these eggs were again 

 covered with water they hatched freely. Eggs that had been kept 

 dry since laid were covered with water September 5th, and 

 hatched. Eggs kept under similar conditions, one series on 

 marsh mud, the other on upland soil, were covered with water 

 September 30th. Five hours later wrigglers were found over the 

 marsh mud ; but three days later none had yet appeared over the 

 upland soil ! 



In one case a number of gravid females were caught in a net 

 with a mass of other material. This was all placed in a jar and 

 the mosquitoes began ovipositing at once, in masses. Only a 

 few of the eggs had turned black twenty-four hours later when 

 they were covered with Avater. A small number of these black 

 eggs hatched ; all of the white examples collapsed. 



Some other experiments were made and from those as well as 

 from the above record, Mr. Viereck concludes as follows : "No 

 black eggs were laid and only one specimen was found with black 

 eggs in it. All eggs laid outdoors (presumably) and in the ex- 

 periment jars (certainly) were white when laid. They changed 

 from white to steel color and then to black, gradually, in one hour 

 and a half. Eggs were laid on moist material, but not into water 

 nor on dry sand or lint. Some hatched over night when the 

 fresh eggs were covered after having turned black; but usually 

 they did not hatch until two or three days had intervened before 

 they were covered with water. One lot placed under water did 

 not hatch in weeks ; these eggs when dried and again covered with 

 water, did hatch. In one jar several hatchings took place at in- 

 tervals of three days. Eggs kept indoors and exposed to the air 

 of the room collapsed. Eggs under the influence of the moisture 

 of a closet did not collapse when in the mold of black grass marsh, 

 but did collapse when the material was ordinary garden soil or 

 lint. Eggs hatched in all percentages of sea water, their further 

 progress depending on food. Larvas died in water at 40 degrees 

 C. (103° Fahr.) ; they survived at 37 degreesi C. (98° Fahr.)." 

 Mr. Viereck is further of the opinion that "whether the eggs will 

 collapse or not after being laid, depends also on the stage of de- 



