FLIES AND OTHER HOUSEHOLD INSECTS 



19 



therefore frequently have exceptionally severe outbreaks of malaria 

 following extensive excavations. This is exactly what would be 

 expected if the above statements are true. 



Appearance and habits. The appearance and habits of the 

 malarial mosquito are important if we wish to avoid malaria. This 

 peculiar form is easily recognized by its spotted wings and, in 

 particular by the characteristic resting position, the beak and the body 

 being in almost a straight line and at a considerable angle to the sup- 

 porting surface. On the other hand, our ordinary mosquitos do not 

 have spotted wings and when at rest the beak and the body form an 

 obtuse angle, the body being approximately parallel with the 

 supporting surface. The wrig- 

 gler of the malarial mosquito 

 occurs in grassy pools, beside 

 streams and is frequently very 

 abundant in collections of water 

 in and about recent excavations. 

 The wriggler of the malarial mos- 

 quito is easily recognized by the 

 absence of a conspicuous air 

 tube, by its resting in a hori- 

 zontal position just beneath the 

 surface film, and the usually 

 bright or dark brown and green- 

 ish colors. The wrigglers of the 

 common mosquito, conversely, 

 have a large air tube at the 

 posterior extremity, invariably 

 rest with the body at a con- 

 siderable angle to the surface of 

 the water and are a dull whitish 

 or yellowish white. The mala- 

 rial mosquito breeds more or less during the warm months of the 

 year, the spotted-winged adults wintering in any shelter, frequently 

 in houses and occasionally flying in midwinter. The capture of 

 chilled specimens on snow banks in early spring is not unusual. 



Control measures. Malarial outbreaks may be prevented or 

 controlled in two ways. The malarial mosquito is very local in 

 its habits. It is comparatively easy, by draining breeding pools 

 and treating those not easily drained, with oil, to eliminate the 

 mosquito and thus do away with all danger of infection. This is 



Fig. 5 Characteristic feeding position of 

 malarial mosquito wriggler in upper figure, 

 and that of the common mosquito in lower 

 figure, (Reduced from Howard, U. S. 

 Dep't Agric. Div. Ent. Bui. 25. n. s. 1900) 



