386 Phylum Arthropoda 



through a small pipe to the west end where it moistens the sand of the 

 grotto. A few potted plants usually are kept on a shelf which is within 

 range of the humidifier. It is felt that vegetation adds something to 

 the naturalness of the artificial habitat in the cage. 



LABORATORY BREEDING OF THE MOSQUITOES, 

 CULEX PIPIENS AND C. FATIGANS 



Clay G. Huff, University of Chicago 



MOSQUITOES of the genus Culex have been bred chiefly for 

 studies on the transmission of avian malaria. They have sub- 

 stituted for Anopheles and human malaria in many studies where the 

 breeding of Anopheles or the experimental inoculation of human malaria 

 has proved impossible or very difficult. When more research has been 

 devoted to the laboratory breeding of mosquitoes it will very probably be 

 found that they are adaptable to many other kinds of research. 



The chief difficulty encountered in trying to adapt either Culex pipiens 

 or C. jatigans (=C. quinquejasciatus) to laboratory conditions is the 

 failure of the adults of the first generation reared in the laboratory to 

 copulate. This is true to a much lesser extent of C. jatigans than of 

 C. pipiens. When adults are reared from larvae which have been either 

 collected in nature or hatched from wild-caught females, the second 

 generation females will readily engorge on blood and will oviposit, but 

 only in a very small number of cases will their eggs hatch. This indicates 

 that copulation has probably not occurred. It should be stated, however, 

 that this is the case when the adults are kept in small containers (no 

 larger than lantern globes) . It seems likely that copulation would occur 

 frequently in large insectaries such as those employed by Boyd for 

 Anopheles. The only method of overcoming this difficulty has been that 

 of breeding entirely from the very few mosquitoes which did copulate 

 in captivity. At times I have been fortunate in securing a raft of fertile 

 eggs from a comparatively small number of females, but at other times 

 many thousands of egg rafts have been secured before any fertile ones 

 would be encountered. In all cases, however, in which a strain of 

 mosquitoes had been secured from females which had mated in captivity, 

 no further difficulty was met in securing copulation of the adults of the 

 succeeding generations. 



FOOD REQUIREMENTS OF ADULTS 



Adults of these two species will survive for fairly long periods on many 

 different fruits, but the one which has proved most satisfactory in the 

 laboratory is cooked raisins. The large varieties are most satisfactory. 

 A beaker is half filled with raisins and covered with water. They are 



