MOSQUITO BIOLOGY 79 



was the dominant species. Captures of adults sent in from this territory 

 always showed vexans present, and that species breeding in a swamp 

 area at Vailsburgh, became common in the sendings of adults from 

 Montclair and South Orange. 



From the Delaware region the open marsh areas almost always 

 turned out vexans in numbers. This is, therefore, essentially a swamp 

 species, but it does not occur in deep or dark swamps. It was never 

 found in the huckleberry swamps of Lahaway, nor in my cranberry 

 swamp collections. 



By far the greatest number of larvae were taken in permanent water 

 areas, but many of the woodland pools in which it occurred were tem- 

 porary in the sense that they usually dried out before the summer was 

 over. It was never sent in from gutters or lot rain pools or from foul 

 waters at any time. It was once found in a barrel at Cold Spring, Cape 

 May County. In New Brunswick a brood was found in a lot pool Au- 

 gust 12, larvae being mature and pupae already present; a second 

 brood was found September 23 in a similar stage, and there may have 

 been a brood in the interval. This is a low springy place, which rarely 

 dries out entirely and which fills readily with even a light rain. The 

 latest collections of larvae were made during the early days of October, 

 adults emerging about the middle of the month. 



Habits of the larvae offer nothing peculiar. Dependent upon atmos- 

 pheric air they are readily destroyed by any of the oil coverings. The 

 pupal stage varies in length according to temperature, but is usually 

 short — two or three days during the summer. 



It is not so readily controlled as the house mosquito, and sometimes 

 causes trouble in jurisdictions outside of those in which it breeds. 



[The eggs appear to be laid on moist soil in depressions in the soil 

 and there is some, but not conclusive, evidence that they are sometimes 

 laid on water. Hatching of some, but not all, of the eggs takes place 

 when covered with water. Sods brought into a screened insectary and 

 covered with water showed repeated hatchings the first season and some 

 hatching each of the two subsequent years. Since no opportunity was 

 afforded for reinfestation, the conclusion follows that the original sup- 

 ply of eggs was the source of all hatching in the three years.] 



