8 BULLETIN 1117, U. S. DEPARTMENT OF AGRICULTURE. 
in connection with E. fumosa in the field. When at the proper stage 
of development, and when touched with a pair of forceps, a minute 
dustlike cloud, similar to that which arises when puffballs are dis- 
turbed, arose from mealybugs that were being collected for labora- 
tory experiments. This cloud was, of course, due to the thousands 
of conidia which were discharged simultaneously when the body 
was touched with the forceps. Without such a stimulus the conidia 
are discharged singly or in very small numbers and are not visible to 
the naked eye. In E. fumosa, however, the force of the discharge, 
compared with that of many other species, is relatively weak, a fact 
substantiated by the somewhat slender conidiophores and the com- 
parative weak conidial papillae. 
It is believed that this method of spore discharge is of great value 
in perpetuating the fungus, in that it aids appreciably in the dis- 
semination of the spores. Citrus mealybugs, while not exactly 
sedentary insects, are more or less gregarious in their habits and in 
nature crawl about over one another and huddle together in bunches j 
hence the value of such a method of spore discharge is not so great 
as it would be, for example, in a parasite of less gregarious insects, 
or of those which are more or less peripatetic in their habits. 
The conidia or spores of this fungus are probably spread from 
colony to colony in part by the process just described, in part by 
insects, particularly ants that frequent mealybug colonies, and in 
part by air currents, in contrast, in this last respect, to the Ascher- 
sonias, which apparently are distributed largely by rain water. 
While a certain amount of moisture is necessary for the best develop- 
ment of most fungi, a slight increase in humidity such as that which 
accompanies a heavy dew is sufficient to cause sporulation in the 
forms like E. fumosa, a fact repeatedly observed in Florida during 
the summer of 1921. 
The second type of reproductive development, which results in 
bodies called resting spores, is totally unlike that noted above, and 
to one not familiar with the organism involved, the identity of these 
resting spores might well be obscure. When resting spores are 
formed there is no external growth whatever upon the insect's body. 
The spherical, smoke-colored resting spores, opaquely black at 
maturity, are formed internally directly from the hyphal bodies. 
They are extremely thick walled and in fact are provided with two 
walls, each of which is very thick, the outer of these, the exospore, 
alone containing the black pigment. It is somewhat indurated 
and cracks rather easily when pressure is applied, separating freely 
from the inner hyaline endospore (PL I, 15). While the germi- 
nation of these bodies has not been observed, it is believed that they 
tide the fungus over periods of unfavorable conditions, such as 
occur, for example, during the winter season in Florida. As already 
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