196 BOTANICAL GAZETTE [MARCH 
account of the group, are as follows: Empusa muscae Cohn, on the 
common house fly; E. culicis, A. Braun, on a small green species of 
Chironomus; Empusa sp., on a large fly; EZ. aphidis Hoffman, on vari- 
ous aphides; E. americana Thaxter, on a blue-bottle fly; and one other 
species, which is the principal one studied in this paper, on the small 
fly, Sciara sp. The ovoid conidia of this last form coincide closely 
with the description of the conidia of EF. montana Thaxter. They 
show decided differences, however, from THAXTER’s drawings of this 
species; and from £. ovispora Nowakowski and E. echinospora Thax- 
ter, with which the measurements of the conidia also almost coincide, 
the form is distinguished by the characteristic zygospores of the 
latter species. While it is possible that, under certain conditions 
unknown to me, this species on Sciara may produce zygospores, yet 
the fact remains that after over a year of continuous observation, I have 
failed to find any resting spores. It is therefore thought advisable to 
give a new name provisionally to this species, which will hereafter 
be referred to as Empusa sciarae. 
Empusa sciarae n. sp.—Vegetative hyphae forming a branching, 
septate mycelium, which in advanced stages is cut up into few- (gener- 
ally 3-5-) nucleate cells. Radial hyphae branched; conidiophores 3-5, 
bearing at each ultimate end a single ovoid uninucleate conidium with 
a rounded basal papilla, 12-16 X 18-25 w. Zygospores unknown. 
VEGETATIVE STAGE. 
My own observations of purely vegetative stages are concerned 
with two forms only, Empusa aphidis and E. sciarae, both of which 
agree with the type described by BREFELD for E. sphaerosperma. In 
all the other species studied, the vegetative condition had ceased 
and conidiophores had grown out from the vegetative hyphae. As 
observed by BREFELD, THAXTER, and others, the insect dies at the end 
of the nutritive period of the fungus; but they do not seem to have 
emphasized the fact that living insects alone must furnish data for the 
study of the vegetative hyphae. After the initiation of the repro- 
ductive period and the consequent death of the insect, the radial 
growth of the conidiophores produces a mass of hyphae which might 
readily be taken, in certain instances, for a vegetative filamentous 
mycelial growth. The probability has suggested itself to the writer 
