262 Annals Entomological Society of America (Vol. VIII, 
The data is summarized in the following table. (Alb—aldz- 
manus; Tar—tarsimaculata; Tae—tentorhynchus; Tit—Man- 
sonia titillans). 
P. Moseuiros CAUGHT UNDER BUILDINGS, GATUN. 
DAYTIME CATCH. 
Anopheline Non-Anophelinz 
eoeaaaeal Days | Periods Total 
Alb altar Tae Tit | Others 
MA f=, )> pe ee Ss: a i ! 
Athens lines 108* 37 | 11,604 | 3,496| 258 | 766 16.161 
PercentrobstOtallesses eater |e: Cake PANEL pe NEN Ga ey 
Average per period........... 0.3 LIES 83. Gay Zep 7.4 155.7 
Males taken. ee eA eMart to 1 | 265 No count kept 
*Four eee lost arouenn invasion of ants. 
Thus it is seen that at least 112 Anopheles lingered under 
each building. Assuming that there are only one hundred 
buildings in Gatun, then each day there harbored under these 
houses no less than ten thousand malarial mosquitos. And 
considering New Gatun, open and unscreened, one must use his 
imagination freely to arrive at some suitable conclusion. Had 
it not been for the thorough treatment given in the past to 
malaria sufferers, and had not a daily search been made in all 
buildings for mosquitos, then surely the malarial rate would 
have leapt upward, probably paralyzing for some time the work 
at this important section. 
All males caught were examined microscopically for the 
presence of blood in the digestive tract, but all tests proved 
negative. In nearly all females of Anopheles blood was found 
but since only a very few showed a very recent meal (upon the 
negro bait), it was reasonable to suppose that the males were 
taken the night previous. Chironomide appeared in great 
numbers at times, and from April 8th to 12th, out numbered 
by far the total mosquito catch. 
The hourly distribution of mosquitos caught during the night 
is given in the following two tables. The actual paucity of data 
permits of no accurate deductions. However, it is significant 
to note the conspicuous catch of 233 tarsimaculata under 
