12 



females, which alone feed on blood, are determined and voracious 

 nocturnal pests. As a rule the insects bite only at night, though 

 according to Grassi* in places where the light is dim the South 

 European P. pajMtasii may also bite by day, and Howlett states that 

 in Bengal in September he has been bitten " in full light at 6.30 a.m." 

 Human beings are generally attacked in bedrooms and dormitories, 

 and it is unusual for Phlebotomus to bite out of doors. The bite is 

 severe ; one observer, writing from Sevastopol, in the Crimea, 

 says that it is " very painful, especially to newcomers " ; and Mr. 

 G. C. Rehling, when forwarding to the Museum specimens of a 

 Phlebotomus, which is a pest during part of the year at Mohammerah, 

 on the Persian Gulf, wrote that : — " They are the most dreaded 

 insects about these parts, their bite being almost as sharp and painful 

 as the application of a red-hot needle. They find their way through 

 all but the finest meshed mosquito-curtains ; mushn curtains 

 effectually keep them out. The bite raises a small rose-coloured 

 eruption, with an inflamed surface round about, and is extremely 

 sore and painful, especially if the hands and feet are the affected 

 parts." Howlett writes : — " The flies not infrequently even crawl 

 under the bed-clothes in their lust for blood, and the bite is to 

 most people extremely irritating. The irritation continues during 

 the whole time that the fly is sucking, this time being about two 

 and a half to three minutes when the operation is allowed to be 

 completed without interruption. The effects vary in different 

 individuals. On myself the bite results in a small reddish pimply 

 sweUing which persists for several days, the itching at first felt 

 subsiding after a day or so. Children are especially attacked, 

 and often seem to feel the irritation very much. Cattle, dogs, 

 frogs, and caterpillars have also been observed to be sucked. The 

 flies generally bite most freely in the early part of the night and just 

 before dawn, but have apparently no very definite period, . . . 

 There is no doubt that variations in humidity and temperature 

 very greatly influence their biting propensities, and a sudden 

 increase of humidity combined with a rise of temperature can 



* Cf. Battista Grassi, "Ricerche sui Flebotomi," Memorie delta Societd italiana 

 delle Scienze {delta del XL.), Serie 3a, T. XIV., p. 370 (1907). 



