412 Journal of Agricultural Research voi. xviii, No. s 



furrow-like depression present in its abdomen. The body, while not 

 limp or flaccid, is soft and pliable; and if a portion of its skin is in- 

 dented, it remains sunken with little or no reaction. The body is never 

 hard and sclerotium-like as in insects infected with Boirytis rileyi, for 

 example. If pricked with a needle no liquid emerges. If torn open 

 entirely, the internal fungus mass is seen to be quite coherent and of a 

 shinv creamy or pink color and gelatinous consistency. A convoluted, 

 almost vermiform structure of the spore masses can easily be recognized 

 with a hand lens. 



Later in the development of the organism the host's body becomes 

 more shrunken and the reddish color more intense, but there is no other 

 change in outward appearance. The body wall is now quite brittle, the 

 slightest shock serving to rupture it. The moist, gelatinous character 

 of the spore masses has disappeared ; and they become typically brick- 

 red in color, dry, dustlike, and less coherent than before. Absolutely 

 nothing remains of the internal organs of the host, and in fact the body 

 appears as, 17 Sorokin (18) first suggested, very much like a minute sac 

 filled with dust. 



The fungus is found in this stage of development when collected in the 

 field in summer, and according to Danysz and Wize (6) it may be 

 seen in the same condition after having overwintered in the soil, a state- 

 ment, it will be recalled, that is in accord with the writer's findings. 



In the foregoing paragraphs the known symptoms of diseased insects, as 

 well as the gross characters of the fungus during the incubation period 

 and the post-mortera aspects of the disease, have been considered. To 

 observe the microscopic characters of the vegetative stages of the fungus, 

 however, many infected specimens have been examined when alive and 

 when killed, fixed, and sectioned. During the first few days of the incu- 

 bation period it is quite impossible to recognize the organism in any of 

 the insect tissues. Upon examination of the blood of infected insects on 

 the sixth or seventh day after inoculation, however, yeastlike cells will be 

 observed floating free in the blood lymph m.ingled with the blood cor- 

 puscles. These yeastlike cells, as will be subsequently shown, form the 

 early vegetative states in the development of the organism; and on 

 account of their similarity to yeasts, the name blastocysts will hereafter 

 be employed to designate them. 



The cells when young are quite regularly elliptical in form, hyalin, 

 measuring 8 microns by 5 microns, and in blood smears occur singly or 

 coherent in pairs, rarely in threes; (PI. 52, I; 53, B). A preparation 

 made from the blood of a diseased insect on the sixth day after inocu- 

 lation will show but few of these bodies, but on the seventh day they 

 become more numerous, and on the eighth and ninth days, under normal 

 conditions, they are strikingly conspicuous, vastly exceeding in numbers 

 the blood corpuscles, which may themselves be abundant. They mul- 

 tiply within the blood plasm by a yeastlike germination, all stages of 



