456 MOSQUITOES OF NORTH AMERICA 



just disappeared, and now quite a little series of specimens was obtained, some of 

 them inactive and apparently dead, but all revived when brought indoors. On 

 the 31st, covered another part of the same territory and found specimens every- 

 where : ' Little holes, not over two inches in diameter, full of water, turned out 

 two or three specimens.' February 1st, collected additional specimens and 

 brought in some of the ice to see whether larv?e were frozen in it. Found that 

 there were none and that the specimens probably kept down below actual frost, 

 if possible. February 7th, it was noted that there was considerable difference 

 between the larvse, as though two or more stages were represented, and, as a 

 whole, they were more advanced than in December ; in the larger specimens a 

 distinct shield-like form of the thorax was now apparent. Collections were made 

 throughout February, and the indoor cultures were under constant observation ; 

 but though the larvae seemed to feed continually they did not grow and spent 

 most of the time at the bottom of the jars ; they do not need air from above the 

 surface. On February 22d, when the ground was snow covered and everything 

 frozen over, holes were made in the ice and active larvse were dipped up from 

 beneath it. The water here was 36 degrees, and in the woodland springs where 

 other specimens were taken it ran 42 degrees. Eain and snow so filled the swamp 

 area that the wrigglers were scattered over so large a territory it was almost im- 

 possible to find them. At this time a series of the specimens was sent to me to 

 be developed in the laboratory, and these arrived in good condition. Through- 

 out March collections were made, and during this time it became so dry that it 

 seemed as if all the larvse must have perished : yet after a rain there were as 

 many as ever. They seem able, apparently, to seek out the wettest places and 

 may even survive for a time in soft mud. April 2d and 3d, collected another 

 lot of over 100 larv^ for shipment to me, and up to that time there had been no 

 pupa seen. The first specimen in the culture material pupated iVpril 4th, and 

 as I obtained the first pupa just a day earlier, this may be considered the be- 

 ginning of the pupation period. The pupa is small in proportion to the size of 

 the larva and the period of this stage is from six to ten days. The last larvse 

 were collected by Mr. Brakeley May 5th, and in nature only one pupa was taken 

 an accidental mingled with canadensis. 



" This record of collections made is an interesting one and proves positively 

 that the larva of C. melanurus lives through the winter in the half-grown con- 

 dition. It is essentially a clean-water wriggler and requires a sheltered locality, 

 like woodland, or an over-grown swamp area, to develop. An area that freezes 

 solid would probably prove fatal, but in spring-water the temperature rarely 

 gets much below 40 degrees, even in the coldest weather, and when there is an 

 ice-covering in the swamp there are the recesses under the edges and the deep, 

 soft mud to serve as retreats. I have no record of the re-occurrence of this 

 larva in the springs before October, and none of the summer collections sent in 

 by Mr. Brakeley contained specimens. Nor have I seen any very small larvae 

 or eggs. 



" A characteristic feature of the species is its remarkably slow growth in 

 spring and the long delay in pupation. The larvse are half grown, or more, 

 before canadensis, or aurifer, are born, yet the latter become adult as soon, or 

 sooner. They are slow in their movements and seem to take life easy, ' like a 

 group of dreamy philosophers,' as Mr. Brakeley puts it. They are bottom-feeders 

 of necessity, since the water in which they live has only a small supply of organic 

 life, but in the leaves at the bottom of the springs and in the mud of the swamp- 

 pools their food is found. So they have well developed trachea in the anal 

 gills and are not dependent upon atmospheric air for their supply of oxygen. 

 This peculiarity is also essential, as their swamp breeding places may and do 

 become completely ice-covered." 



