17 
tribution of the 145 mosquitoes was as follows: 35 in the chicken 
house, 9 under the cabin, 101 within the cabin. 
In order definitely to establish the fact that hibernation of Anoph¬ 
eles exists in this region certain conditions must be present. These 
would include the absence of propagation during the cold period; 
certainly no emergences should exist, or, obviously, the criterion for 
the overwintering of infections will be upset. The presence of eggs 
and young larvae will somewhat complicate the findings unless it can 
be proved that these forms are lying dormant during the entire 
winter; otherwise certain calculations will be upset by the forth¬ 
coming new brood. 
The absence of males appears to establish what is probably the 
most stable criterion of hibernation, or at least one which gives a 
certain indication that a new brood is not present. It has been ob¬ 
served, upon numerous occasions, and by other workers, that the 
product of the first emergences are usually males, and that the total 
number of the two sexes is approximately equal. 
All of the evidence that it is possible to offer in this connection 
favors the assumption that the mosquitoes obtained in the months 
of February, March, and April are of the fall and winter brood. 
In addition to this, a painstaking and persistent search was con¬ 
ducted for the eggs, larvae, and pupae of Anopheles throughout the 
watercourses and swamps of the 15 plantations situated in Bolivar 
and Washington Counties. Not before May 1 were Anopheles 
larvae taken from the natural habitats, although larvae were ob¬ 
tained under artificial conditions in the laboratory on April 21. 
These were produced from a specimen of Anopheles quadrimacvlatus , 
caught while biting my arm on April 6 while in the woods. The 
specimen was captured and fed again April 10. It died April 16 
while ovipositing, having laid 10 eggs in a glass dish containing 
water. The eggs hatched after five days, at an average noon tempera¬ 
ture of 23.5°-26° C. This, however, is by no means a true index 
of what occurs in nature, as it has been possible to remove gravid 
females from a profound state of hibernation in cold weather and, 
after a meal of blood, to induce them to lay fertile eggs at room 
temperature. Certain inferences, however, may be drawn from this 
phenomenon, namely, that, unless we concede a parthenogenetic 
relationship, the hibernating females are doubtless fertilized some¬ 
time previous to the inactive period; that the males no longer func¬ 
tioning do not hibernate, that the appearance of males in the spring 
is a certain sign of the propagation of the spring generation. 
The^ initial appearance of the young stages in nature occurred May 
2, when larvae less than twice the length of the egg were collected 
in several watercourses. Larvae, in numbers enough to attract at¬ 
tention, did not occur until May 14, when they were found during a 
