208 MOSQUITOES OF NORTH AMERICA 



feeding. The voracity of the animals is incredible. An ordinary Ciilex, after it 

 has sucked its fill, flies away. These Anopheles, however, are not satisfied with 

 this but continue to suck, making more room by discharging the surplus through 

 the anus. At first they discharge the faeces and intestinal liquid, but afterwards, 

 drop by drop, pure blood follows. So, before it chooses to fly away, it flushes its 

 digestive tract with three to four times the amount of bood which would have 

 been necessary to fill its stomach." 



Grassi, in Italy, was the first to study carefully the habits of Anopheles and 

 his observations still stand unsurpassed. He believes that the normal food of 

 Anopheles is blood, and, if they can find it, exclusively that of warm-blooded 

 animals. They prefer the blood of mammals, but he found that sometimes they 

 would, as it seemed with some reluctance, suck the blood of birds (poultry, 

 sparrows and hawks). Grassi does not believe that there is a predilection for 

 particular mammals, but that they are attracted in proportion to the size of the 

 animal, the larger animals appealing more strongly to the olfactory sense of the 

 mosquitoes. He found that frequently, when a man and horse were near each 

 other, the horse would be bitten many times before the man was bitten at all. On 

 the other hand, in the case of a man and rabbit, the man is generally attacked 

 first. 



Grassi found that under proper conditions Anopheles will bite in the open, in 

 houses and in stables. He states that in malarial regions it very often happens 

 that, in the evening, when persons are sitting at their doors, they are attacked 

 by great clouds of Anopheles. He found that in the summer the Anopheles, 

 after having procured a blood-meal within the house, seeks a hiding place 

 outside where it can digest the food. It does not fly far but hides in the foliage 

 near by and returns to the same place to obtain another meal of blood. During 

 the day they remain quiescent among the herbage, upon the under side of leaves, 

 selecting a spot where they are best protected from sun, rain and wind. 



Grassi found that in the winter the Anopheles sought shelter in houses and 

 particularly in stables, and that, while with low temperatures they remained 

 quiescent, if the temperature rose they would suck blood. The preference of 

 Anopheles for stables has been repeatedly observed. Kinoshita, in Formosa, 

 found Anopheles abundant in stables and he utilized these in his studies on 

 malaria, for it proved that such Anopheles were all free of malarial parasites. 

 Miihlens, in his studies of some malarial epidemics in northern Germany, made 

 some interesting observations on the preference of Anopheles for stables. In 

 the spring of 1907 and 1908, at Bant in the vicinity of Wilhelmshaven, he found 

 the Anopheles preponderatingly in the wann stables of cattle and hogs, where 

 they had hibernated. They were rare in the cellars of houses, while, on the con- 

 trary, Culex were abundant in the cellars but rare in the stables. The Anopheles 

 fed through the winter and showed a preference for the animals over man. The 

 stomach contents of the Anopheles from stables were tested by the Uhlenhut 

 process and it was found that they consisted of the blood of cattle or hogs, ac- 

 cording to whichever animal they happened to have been associated with. As 

 already pointed out by Grassi, two factors probably determine the preference of 



