The mycelium is richly branched. The family is a transitional step to
the conidia-bearing Zygomycetes, since the oospores of many members of
this family arise, and are formed, like zygospores.
Order 1. =Entomophthoraceæ.= Mycelium abundantly developed. This
most frequently lives parasitically in living insects, causing their
death. The conidiophores forming the conidial-layer project from the
skin, and abstrict a proportionately large conidium which is ejected
with considerable force, and by this means transferred to other
insects. These become infected by the entrance of the germ-tube into
their bodies. The spherical, brown resting-spores develope inside the
bodies of insects and germinate by emitting a germ-tube.
GENERA: _Empusa_ has a good many species which are parasitic
on flies, moths, grasshoppers, plant-lice. The conidia emit a
germ-tube which pierces the skin of the insect; a number of
secondary conidia are then produced inside its body, by division
or by gemmation similar to that taking place in yeast, each
of which grows and becomes a long unbranched hypha, and these
eventually fill up the body of the animal, causing distension
and death. Each of these hyphæ projects through the skin,
and abstricts a conidium, which is ejected by a squirting
contrivance. The best known species is _E. muscæ_ (Fig. 85),
which makes its appearance epidemically towards autumn on the
common house-fly, and shows itself by the dead flies which are
found on the windows and walls attached by their probosces,
distended wings, and legs. They have swollen abdomen, broad
white belts of hyphæ between the abdominal rings, and are
surrounded by a circle of whitish dust formed by the ejected
conidia.--_Entomophthora_ sends out, at definite places, from
the mycelium hidden in the insect’s body, bundles of hyphæ,
which serve the purpose of holding fast the dead insects, the
ramifications attaching themselves to the substratum: the
conidiophores are branched, the conidia are ejected by the
divisional walls between the hyphæ and the conidia dividing into
two layers, those which terminate the hyphæ suddenly expanding
and throwing the conidia into the air. _E. radicans_ makes its
appearance epidemically on caterpillars.
=B.= Asexual reproduction by zoospores or conidia.