CHAPTER V.—COMPARATIVE REVIEW.—ENTOMOPHTHOREAE. 159 
a shrivelled drying mummy, surrounded by a circle of spores or gonidia which have 
been thrown off. The latter are capable of immediate germination, and do germinate 
if duly supplied with moisture, either emitting a germ-tube which penetrates at once 
into the body of a suitable insect and goes through the process of development above 
described, or only producing short tubes from the extremity of each of which a new 
secondary gonidium with the same qualities as the primary is abjointed. The 
gonidia soon lose the power of germination; in Empusa Muscae, for example, it does 
not continue beyond about fourteen days. 
The Fungi are limited to the above course of development in most of the insects 
which they attack. In some cases, however, few or no gonidia are formed and 
zygospores OT azygospores are ultimately developed, and in most species inside the 
body of the insect. Nowakowski gives the following description of the formation 
of zygospores in Entomophthora ovispora and E. curvispora. The cells of adjacent 
hyphae develope an H-shaped union by means of the necessary processes, and 
establish an open communication at the point where the processes are in contact with 
one another. Then a spherical protuberance makes its appearance near the 
point of union, either on the cross-bar of the H or close to it, and receiving 
as it grows the entire protoplasm of the conjugated pair of cells is finally delimited 
by a membrane, and becomes.a zygospore in the sense in which the word is used in 
the case of Piptocephalis. 
No azygospores have been observed in these species. But Entomophthora 
radicans and the species of Empusa examined by Nowakowski have only azygospores 
which are produced without conjugation as lateral outgrowths on the mycelial tubes 
or acrogenously like the gonidia, as in the species named by Nowakowski Lamia 
culicis. It would appear therefore that there is a difference in the matter of con- 
jugation in the different species similar to that which is found in the Saprolegnieae 
as regards the presence or absence of the antheridial branches. Both zygospores 
and azygospores become resting spores in the same way. The membrane 
becomes much thickened and is differentiated into a thick usually bright yellow 
episporium with a smooth surface in most species, and a thinner endosporium, while 
a large, globular, nearly central drop of oil separates in the protoplasm from 
the general finely granular turbid mass. The mycelium is dissolved and disappears 
after the formation of the resting-spores, which are therefore the only remains of the 
plant in the mummified body of the insect. Their germination was observed 
by Nowakowski in Empusa Grylli, and consists in the emission of a short tube, the 
promycelium, which forms a gonidium at its apex; the gonidium is abjected, in the 
same way as gonidia from the gonidiophores described above. 
The above account is a summary of Brefeld’s and Nowakowski’s observations. The 
differences in the statements of the two writers with regard to conjugation are to be 
explained by the different behaviour of different species. The genetic connection once 
frequently assumed between the Entomophthoreae and other Fungi, especially Saccharo- 
mycetes and Saprolegnieae, is a subject for the history of botanical errors. Information 
on the point will be found in the works cited below. 
_ Cohn has described as Tarichium a species which preys on ground-caterpillars ; it 
has only resting-spores with thick walls roughened on the outside with warts, and may 
perhaps belong to this section. In Nowakowski’s opinion both the development and 
affinity require to be more closely examined. 
