REPORT ON MOSQUITOES. 215 



gether nearly 1,000 examples were examined by Mr. Dickerson 

 and myself. There were large specimens and small specimens, 

 fresh specimens and old specimens, specimens that had fed re- 

 cently, some that had almost completely digested a meal of blood 

 and some that had to all appearance never fed at all; but none 

 with eggs in any stage of development and none with the char- 

 acteristic inflated yet hollow abdomen of the female that has 

 laid her eggs. 



The larvae have been sought in fresh water and salt, in clean 

 water and foul ; in the woodland and in the open ; but up to the 

 present time without success. Larvse have been found whose 

 adults are rarely or never seen, but that of this common species 

 has escaped us thus far. Usually the species occurs in small 

 numbers, though in 1903 it was several times sent in among the 

 house mosquitoes, especially from Arlington; but in 1904 not an 

 example was turned in, except by Mr. Brakeley, to whom we 

 owe whatever knowledge we have of the adult. Mr. Brakeley 

 believes that this is a migratory form, basing his belief upon the 

 facts that, despite diligent collecting under varying conditions, 

 he never found a male, and that they came in under the same 

 conditions and with cantator and sollicitans. May 27th in 1903 

 and May 29th in 1904 marked the first appearance of the insects 

 at Lahaway and a day or two later the swarm was in possession. 

 It is not suggested that pertiirhans comes from the marshes ; 

 simply that it does not breed on the place and comes in from some 

 outside point. 



It is one of the fiercest and hardest biters that we have and 

 Mr. Brakeley writes : "As against pertiirhans, undershirt, pants 

 and drawers are no protection; they will bite clean through all." 

 Nor are they at all timid or deliberate in the attack ; but rather 

 at once dive for the nearest point that offers a chance to make 

 a puncture. They have no scruples about entering houses and 

 for a time formed the only annoying species in Mr. Brakeley's 

 office and bed room. I have already indicated that it was 

 received from other points as a house mosquito. The latest date 

 for the species is August 26th from Lahawa}^ while the earliest 

 dates are those above given for the same place. 



In order to determine, if possible, how generally this species 

 was distributed, Mr. Brakelev collected in the late evening for 

 a radius of half a mile or more from his house and found it 

 everywhere, though not, of course, equally abundant in all places. 

 Attempts to collect during the day proved failures, and inciden- 

 tally proved that the insects do not seek concealment in the grass 

 during the day. At early dusk they appear, coming apparently 



