8 BULLETIN 111*7, U. S. DEPARTMENT OF AGRICULTURE. 



in connection with E. fwniosa 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. fmnosa, 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 meal3^bugs, while not exactly 

 sedentary insects, are more or less gregarious in their habits and in 

 nature crawi 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 humidit}^ 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 a/t 

 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 exosj)ore, 

 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 



