194 BOTANICAL GAZETTE [MARCH 
inclined to believe that the disease is continued over winter on flies 
in warmer regions, and that it migrates northward with the insects on 
the return of summer; the fallacy of which theory THAXTER has 
pointed out. 
THAXTER (’88) in his account of the Entomophthoreae of the 
United States, gives the results of morphological studies based on a 
considerable number of new as well as old forms. This author dis- 
agrees with BREFELD in regard to certain important points. In the 
first place, he maintains that the vegetative growth in E. sphaero- 
sperma is not filamentous in all cases, as is stated by BREFELD, and he 
appears to be inclined to think that both the filamentous mycelium 
and the broken-up, budding segments may occur in the same form 
under different conditions. He asserts that the usual multiplication 
of the hyphae is not by branching and continuous growth but by the 
formation of ‘‘ hyphal bodies,” which “ consist of short thick fragments, 
of very varied size and shape, that are continually reproduced by 
budding or division, until the insect is more or less completely filled 
with them.’’ But he continues further: ‘‘In cases where a direct 
mycelial growth follows the entrance of the hypha of germination, 
if indeed such instances occur, this mycelium must fall to pieces 
into hyphal bodies, before the commencement of growth the direct 
object of which is reproduction, in a fashion resembling that above 
described at a similar stage for Conidiobolus’’ (p. 140). This con- 
ception of reproduction by means of ‘‘hyphal bodies, ’’ however, 
for reasons that are stated later in this paper, must be abandoned, 
at least as a generalization. 
The segments of the vegetative hyphae, or “ hyphal bodies” as 
THAXTER terms them, under unfavorable conditions may each form 
a thick-walled resting chlamydospore; or, when the conditions are 
favorable, they may at once proceed to develop into the fructifying 
state. In the latter case, according to this author, each hyphal seg- 
ment sends out one or two (in some species more) hyphae which 
develop into conidiophores. In the simplest case, a simple conidio- _ 
phore grows directly to the outer air and produces a single conid- 
ium (Empusa muscae, e. g.). Or, the conidiophore may become 
compound and produce a set of conidia. Or, under very favorable 
conditions, ‘‘a single primary hypha may branch indefinitely, each 
