244 



SCIENCE. 



[N. S. Vol. XVII. No. 424. 



that had been left with their parents had 

 completely disappeared in six weeks, al- 

 though other food was liberally supplied. 



The Effect of Low Temperatures on Mos- 

 quito Larvce: John B. Smith, New 

 Brunswick, N. J. To be published in 

 Final Rep. of Mosquito Investigation, 

 N. J. 



Mosquitoes were, until recently, sup- 

 posed to hibernate as adults, and it was 

 believed that low temperatures cheeked or 

 absolutely prevented the development of 

 larva3. 



A series of observations made in New 

 Jersey during the winter of 1901-02 and 

 the last months of 1902 indicate that even 

 freezing temperatures do not entirely pre- 

 vent development, though they may delay 

 it. The species vary in method of hiber- 

 nation, some living through as adults, some 

 as larvse, and some in the egg stage. None 

 winter as pupa. The larvae that hibernate 

 may be frozen solidly in ice and will come 

 to no harm. Temperatures down to zero 

 (Fahrenheit) do not prevent final matu- 

 rity, and the freezing and thawing may be 

 repeated several times during the winter 

 without bad effects. 



Of species that hibernate as adults, many 

 larvse of the later broods are caught by 

 frosts and may be ice-bound for a time 

 without harm. The larvffi of Culex pun- 

 gens have been observed in a pail coated 

 with ice one fourth inch thick, barred ab- 

 solutely from access to the outer air for 

 several hours, and they completed their 

 development in due time after the ice dis- 

 appeared. Pupffi of the same species have 

 been frozen in a solid mass of ice and 

 transformed into adults later. 



Concerning Anopheles punctipennis the 

 same observation has been made, and both 

 larvffi and pupce were taken from pools 

 that had been completely ice-coated for 

 several hours. 



Species which in the larval stage have 

 survived freezing, or at least being bound 

 in ice-covered pools, are Anopheles puncti- 

 pennis, Culex canadensis, Culex sylvestris, 

 Culex pipiens, Culex restuans, Culex ter- 

 ritans, Aedes S7nithii and Corethra brake- 

 leyi. Of Aedes smithii it is positively 

 known that it winters in the larval stage 

 only ; of Anopheles punctipennis and Culex 

 pipiens it is positively known that they 

 winter as adults only. Of C. canadensis 

 and C. sylvestris it is believed that they 

 winter in the egg stage; but it is not cer- 

 tain that they do not also winter as larvse. 

 Of C. territans it has been said that it 

 winters as an adult, but the larva are 

 found very late in winter and very early 

 in spring. 



Notes on the Natural History of Some of 

 the Nudibranchs : W. M. Smallwood, 

 Syracuse University, Syracuse, N. T. 

 To be published in Bull. Syracuse Uni- 

 versity. 



During the past summer at Woods HoU 

 the following nudibranchs were secured: 

 Montagua gouldii, Montagua pilata, Doris 

 bifida, ^olis papillosa and Elysia chloro- 

 tica. The classification is according to 

 Verrill. 



Montagua gouldii was found in large 

 numbers in the colonies of Tubularia cro- 

 jua pilata was taken by 

 Doris and JEolis were found 

 at low tides on rocks and weeds. Elysia 

 was taken in a tow-net, but did not lay 

 while under observation; the other forms 

 laid very freely in common glass aquaria. 

 One hundred and fifty specimens of 

 Montagua gouldii laid 929 masses of spawn 

 within nine days after being brought into 

 the laboratory, and hundreds of egg 

 masses might have been collected from the 

 hydroids from which these were taken. 

 The spawn was scattered or laid in nests; 



