CYTOLOGICAL STUDIES ON THE ENTOMOPHTHOREAE. 
I. THE MORPHOLOGY AND DEVELOPMENT OF EMPUSA.'" 
EDGAR W. OLIVE. 
(WITH PLATES XIV AND XV) 
THE general development of the Entomophthoreae and the exter- 
nal morphology of its various members have been studied by a number 
of investigators. For a detailed review of the literature pertaining to 
the group, the reader is referred particularly to the papers of BREFELD 
(’71,’81,’84) and of THAXTER (’88). 
CoHNn’s (’55) results in his classical paper on the developmental 
history of Empusa muscae have been in certain respects considerably 
modified by later investigation. According to him, the fly first be- 
came diseased and the fungus followed as a consequence. The first 
indications of the disease which CoxN could find in the blood of 
the fly were numberless minute globular or irregularly shaped bodies, 
whose presence he could not explain otherwise than by the assump- 
tion of spontaneous generation (p. 334). 
These bodies, according to him, grow larger, become globular 
or ellipsoidal, and finally grow into the filament, which, by the 
formation of partitions, becomes the three-celled hypha characteristic 
of the mature fungus and consisting of spore, stalk-cell, and root-cell. 
This three-celled character of the hyphae of Empusa muscae was 
disproved, however, the next year by LeBert (’56) and later by 
BREFELD and others. 
Every investigator who has attempted to infect insects artificially 
has testified to the difficulties which he has encountered. COHN 
(’55, P- 342), in speaking of his own lack of success, wisely empha- 
sizes the caution which should characterize such experiments, noting 
that one should be certain that the insects experimented with are not 
already stricken with the disease, a more difficult task than would 
at first appear. 
I am under obligation to the Carnegie Institution of Washington for grants, 
which have rendered possible this investigation. 
Botanical Gazette, vol. 41] [192 
