DISEASE-BEARING AMERICAN MOSQUITOES 29 



breed in artificial containers. A. quadrimaculatus has also been 

 known to breed in salt marshes and other brackish water and, 

 rarely, in sewage-polluted water. 



A. quadrimaculatus enters buildings very readily, and the 

 slightest opening in the screening will be taken advantage of. 

 If the size of mesh of the screen is less than No. 16 or No. 14, 

 painted, small-sized individuals will be certain to get in. A. 

 quadrimaculatus enters inhabited buildings at night and makes 

 its exit early in the morning, unless so gorged with blood as to be 

 unable to pass through the screen. In this case it may be 

 observed resting on the screen next clay. 



It has been found, by means of the recovery of stained speci- 

 mens previously liberated, that A. quadrimaculatus sometimes will 

 travel more than a mile, although it is not believed that, under 

 average conditions, the usual flight is as much as that. It is 

 believed that A. quadrimaculatus could become of sanitary 

 importance more than a mile from its breeding-place only if the 

 breeding-place were very extensive and production therein very 

 heavy. 



A. CRUCIANS WIED 



As compared with the other Anopheles, the wing of the crucians 

 is more dusky and the veins, thereof, more prominently marked. 

 The characteristic marks are three small, blackish spots- 

 patches of black scales — on the sixth wing vein, thoracic end, 

 posterior margin. If the specimen be very old, the end spot may 

 be indistinct. 



The crucians has been called the "clay-light Anopheles" 

 owing to its habit — in contrast with that of A. quadrimaculatus 

 and A. punctipennis — of biting during the day and early evening. 

 A. crucians enters dwelling-places fully as readily as does A. 

 quadrimaculatus; it may also frequent privies and be abundant 

 underneath houses. Despite these circumstances, A. crucians is 

 believed to be somewhat less efficient as a vector of malaria 

 than A. quadrimaculatus. 



A. crucians appears to be able to travel somewhat further than 

 A. quadrimaculatus, recent tests indicating that this species can, 

 on occasions, fly as far as 7,000 feet. 



In its life-habits, A. crucians is similar to A. quadrimaculatus. 

 It is not so fastidious as to character of breeding-place, however, 

 and fairly frequently may be found breeding abundantly in 



