288 
MONICA TAYLOR. 
(2) The fusion of three pairs of homologous chromosomes 
at some early stage in the life-history, this fusion remaining 
permanent throughout later divisions. In the discussion 
preceding the summary it was stated that the question could 
not be settled until the fertilisation process had been 
examined. 
This work on the cytology of Culex, as stated in the intro- 
duction of the above paper, had been undertaken because of 
the importance of the conclusions given by Miss Stevens in 
her paper, entitled “The Chromosomes in the Germ-cells of 
Culex ” (3). 
The second of the alternative suggestions offered above is 
a modification to meet the particular needs of the case of 
Culex pipiens of Miss Stevens’ statement that: “Para- 
synapsis (parasyndesis) occurs in Culex in each cell 
generation of the germ-cells, the homologous maternal and 
paternal chromosomes being paired in telophase, and remaining 
so until the metaphase of the next mitosis.” 
Difficulties in obtaining the necessary material, and in tlio 
technique connected with the food supply of the imagines, 
delayed, for the time being, the examination of the fertilisa- 
tion processes, and prevented the demonstration of the whole 
history of oogenesis. 
Dr. Woodcock’s paper “On ‘Crithidia’ fasciculata 
in hibernating mosquitoes (Culex pipiens) and on the 
question of the connection of this parasite with a Trypano- 
some ” (5) has, however, incidentally filled up some of the 
gaps left in the history of oogenesis, and, in this paper, the 
technique of artificial rearing of Culex pipiens in all 
stages of its life-history has been described. 
I should like to take this opportunity of thanking 
Dr. Woodcock not only for sending me a Reprint of this 
paper, but also for giving me full details in writing of his 
experiments, by which I have been enabled to repeat his work 
with similar success, and also, as will be shown later, to con- 
firm his statement that “Culex pipiens is essentially the* 
British mosquito which likes Avian blood.” 
