36 The Philippine Journal of Science ms 



with no injury to the insect. The cover glass makes the use 

 of higher powers convenient, and the details of the larvae are 

 more clearly seen than when examined without a cover. 



In many of these experiments I have used as mosquito cages 

 lantern chimneys as described by Darling. For the greater part, 

 however, I have used the common wooden sieves sold for a few 

 cents each in eastern markets. These were used at the sugges- 

 tion of Dr. H. P. Hacker, and I have developed the idea and 

 have found these sieves a most useful sort of cage. A hole about 

 one inch in diameter is cut in the middle of the wooden side, and 

 a piece of mosquito netting is tied over the open end of the 

 sieve. When it is desired to introduce into the cage mosquitoes 

 as they are bred out, larvae or pupae are placed in a wide-mouthed 

 glass jar, over which a piece of mosquito netting or cloth is 

 tied. A hole is cut in the middle of the cloth about the size of 

 the opening in the side of the sieve. The sieve is then tied firmly 

 over the jar in such a position that its lateral opening commu- 

 nicates with the opening in the cloth on top of the jar. If the 

 jar is nearly filled with water, practically all of the mosquitoes 

 on emerging will enter the sieve. One has then only to remove 

 the sieve, place a flap of its netting over the lateral opening, 

 and push the string down to hold it in place. The cage is then 

 ready to be exposed to a gamete carrier, immediately or after 

 the mosquitoes have been kept long enough to become hungry. 

 Or it is easy to take out the mosquitoes by means of test tubes 

 introduced through the lateral opening and examine them singly 

 before placing them in cages for feeding. 



In exposing such cages to a gamete carrier, the carrier lies on 

 his back, the thighs or calves are moistened with a bit of wet 

 cotton, and the cages are placed flat under them in close contact 

 with the skin. A blanket is then placed over the lower part 

 of the patient's body. Towels or other cloths may be tied around 

 the cages so as to secure a better contact with the patient's skin. 

 Several cages may be placed under the same carrier at the same 

 time. 



In my experiments feeding was usually done in the early fore- 

 noon or in the late afternoon. It was not found necessary to 

 wait until nightfall. Mosquitoes usually fed well if exposed a 

 day after emerging. Anopheles rossi often bit well within 

 twelve or fifteen hours after the pupal stage. In one lot of 121 

 females of A. rossi over 85 per cent took blood within less than 

 fifteen hours after emerging. 



After feeding, the cages may be placed metal side down on 



