382 Phylum Arthropoda 



When females are required for experimental purposes they are sep- 

 arated from the males by means of the catching tube after transfer from 

 the eclosion cage to a small bobbinet cage to be transported to the 

 laboratory. The males and surplus females are released in the insectary 

 to join the colony. A pledget of cotton moistened with a 10% dextrose 

 solution is placed over the top or side of the cage. We have found that 

 longevity of the females is greatly increased if they have fed on dextrose 

 some days prior to their application to a malaria patient. 



The females are carried to the laboratory and placed in a 20 C. in- 

 cubator, where they remain 2 or 3 days, or until they have all had a 

 feeding of dextrose. They are then put into a large bobbinet storage 

 cage holding approximately 300 mosquitoes and placed in a Frigidaire, 

 where they remain until required for use. 



When females are to be infected, they are starved about 2 days before 

 they are to be given the infecting blood meal. They will take a feed 

 better if they are given their opportunity from 7 to 10 days after eclosion. 



It is desirable for various reasons to infect mosquitoes on their first 

 feed. On this occasion they can ingest a larger volume of blood than 

 at any subsequent time. Immediately after feeding, the insects which 

 fed should be separated from those which did not, and the latter are 

 discarded. This separation must be done with great care in order to 

 avoid injury to the distended mosquito. 



After mosquitoes have received their initial infecting feeding on an 

 infectious human subject, their subsequent nutritional or conservation 

 feedings are taken from a rabbit. This rabbit is secured to an operating 

 board and the hair is clipped from its side over an area sufficient to 

 permit the application of the cage end directly to the skin. We find it 

 very important to first apply the mosquitoes to the rabbit the day fol- 

 lowing their infective feeding, and to then employ great patience in 

 order to persuade the maximum number to feed on the animal. There- 

 after during the extrinsic incubation period, they are given an oppor- 

 tunity to feed every third day by exposing the caged insects to the 

 rabbit for about fifteen minutes. After sporozoites are present in the 

 salivary glands of the mosquitoes, the cages are transferred to the 

 Frigidaire. They are then only allowed to feed on the rabbit once a 

 week. Pledgets of moist cotton are kept on each cage to maintain 

 humidity at saturation and to give the insects an opportunity to drink. 

 All cages are examined daily for the detection of dead mosquitoes, which 

 are removed for dissection. After they become infective, they are stored 

 in a Frigidaire at a temperature varying from 2 to 17 C. except when 

 they are permitted to feed weekly for purposes of conservation. Mos- 

 quitoes are transported to and from the hospital in a picnic refrigerator. 



Insects that are incubating an infection are kept in a cool incubator, 



