12 



The veins of the wings are clothed with dark brown scales. The 

 first submarginal cell is longer than the second posterior cell and the 

 base of the former is nearer the root of the wing. 



Biting. — The male insect does not bite; it lives almost exclusively 

 on vegetable and fruit juices. In the females, however, a feed of 

 blood is a necessary condition precedent to egg laying. At summer 

 temperatures this insect will digest a full meal of blood in about 48 

 hours. If disturbed in the act of feeding it will fly away, but will 

 return and attempt to finish its interrupted meal. In this way one 

 infected mosquito in its efforts to obtain one full meal may bite several 

 individuals, and so may, almost simultaneously, produce more than 

 one case of yellow fever. 



It. has long been observed that communication with an infected 

 town is distinctly safer during the day than 'after dark. In an effort 

 to explain this phenomenon the French yellow fever commission first 

 suggested, then made some experiments which appear to show that 

 under natural conditions the yellow fever mosquito, after the first 

 week, ceases to bite during the day and bites only at night — that is, 

 between 5 p. m. and 7 a. m. These results are not, however, alto- 

 gether in harmony with the observations of others, and there are 

 cases recorded showing that yellow fever may be contracted by visit- 

 ing an infected house during the day." We must conclude, therefore, 

 that the Stegomyia calopus, young or old, may bite at any time dur- 

 ing the 24 hours, though probably it is most vicious about dusk and 

 about dawn. The female is impregnated almost immediately after her 

 birth, and then proceeds to seek a blood feed; 3 or 4 days after this 

 she is. ready to lay her eggs. 



Breeding places.— -The Stegomyia calopus appears to be strictly a 

 house mosquito — a domestic though not domesticated animal. Her 

 breeding places, therefore, may be expected, and actually have been 

 found to be any collections of water in and about habitations, such 

 as cisterns, wells, water barrels, tubs or jars with or without water 

 plants, sagging roof gutters, more or less broken and discarded 

 crockery, bottles and tins, fountains (not containing fish), cemetery 

 vases, baptismal and other fonts in churches, chicken or horse 

 troughs, grindstone troughs, and tubs or barrels containing water 

 which has been softened and made more or less alkaline by the use of 

 ashes. The Iarvse have been found in tin cans containing fecal matter, 

 in cesspools, and in some natural collections of water formed by leaves 

 of certain tropical plants, such as the palm and century plant. Ordi- 

 narily, she does not seek street puddles or gutters, favorite breeding 

 places for Culex taeniorhynchus and Culex pipiens (=pungens), though 

 her larvae have been found in these situations. 



a Carter, 1901b, p. 936. 



