NECESSITY OF BLOOD AS FOOD 277 
RELATION OF FOOD TO OVIPOSITION. 
Finlay found that the female Aédes calopus could not develop its eggs without 
having obtained blood. “Nearly all the females captured after having filled 
themselves with blood, at the end of a few days lay eggs, while those which are 
fertilized and have not been able to obtain blood die without ovipositing.” He 
believed furthermore, as calopus does not lay all its eggs at once, that it needs 
several blood meals to dispose of all its eggs. 
Reed and Carroll confirmed the observations of Finlay and found that the 
interval between a blood meal and oviposition may vary from two to thirty days. 
“ As a rule, the eggs are laid within seven days; sometimes a second or third 
meal of blood is taken before any eggs are laid.” 
The French commission also found that in calopus blood food is indispensable 
for the reproduction of the species. They found that whether the female sucked 
blood before or after copulation the eggs would be deposited within a few days. 
If a fertilized female is fed on sweet substances the eggs will not develop; if 
afterwards, for example after 15 or 20 days, the female is fed blood the eggs 
will then develop. In the latter case the interval between the blood meal and 
oviposition will be about the same as when it has fed on blood soon after being 
fertilized. In one of their experiments 10 females and 15 males were placed to- 
gether in a cage on the same day that they had issued from pup». Three of the 
females were taken out 48 hours afterward and induced to suck blood. Of these 
three females one deposited eggs after four days, the other two after six days. 
After 18 days three of the females which had been fed only upon honey, and 
which had not oviposited, were allowed to suck blood; they deposited eggs five 
days after the blood meal. The four remaining females which had not been 
allowed to suck blood died without depositing eggs. The French observers state 
that the result is the same whether the females are allowed to bite man or some 
other warm-blooded animal, but that it must be remembered that calopus shows 
more or less repugnance towards any other animal. 
Goeldi, at Para, made a series of experiments with similar results. One of his 
conclusions is that blood food, in hastening the development of the eggs, shortens 
the life of the mosquito. On the contrary a diet of honey prevents the develop- 
ment of the eggs and thus prolongs life. He found that by feeding the females 
with honey the power of depositing fertile eggs may be kept latent for long 
periods. He determined, also, that unfertilized females would lay eggs when fed 
with blood but that these eggs would not produce larve (pseudo-partheno- 
genesis). Goeldi found that the interval between the first blood meal and 
oviposition averaged 3.7 days=88 4/5 hours. The female, after having de- 
posited all her eggs, dies, either immediately afterward or at the most within a 
few days. The longest time that a female survived oviposition was 14 days. 
Goeldi determined that the shortest interval between a blood meal and ovi- 
position was two days, the longest interval seven days. He gives observations in 
which eggs were laid one day after a blood meal, but in these cases the females 
were captured and probably had already sucked blood. On one occasion, in an 
experiment with captured females, eggs were laid after blood had been withheld 
