CHAPTER VII.— PHENOMENA OF VEGETATION.—PARASITES. 371 
by Peyritsch! in the case of the house-fly. The health of the insect attacked by 
these epiphytes seems to be very little disturbed. 
The development of the Entomophthoreae which attack insects has also been 
given above (page 158). We may add here that the body of the insect is occupied in 
essentially the same way as by the species of Cordyceps which will be described 
below. The Entomophthoreae, like the Laboulbenieae, are, as far as is known, strictly 
obligate parasites, and go through the whole course of their development, with the 
exception only of a brief stage of germination, in and on their host while it is either 
still alive or recently killed by their vegetation. 
The life-history of the species of Cordyceps which attack insects is more 
complicated. Cordyceps militaris, as examined in caterpillars, may be taken. 
C 
N 
A 
C B 
N A) 
FIG. 165. Cordyceps militaris, Fr. A secondary spores from the asci germinating in water on a microscopic slide. 
« a single spore with one of its germ-tubes erect and b d, its ity and the b hes having formed chains of 
gonidia. & three secondary spores germinating; the germ-tube of one of them has risen into the air and formed a chain of 
gonidia on its apex. B extremities of hyphae which have p igh the chi skin of a caterpillar, have reached 
its inner surface and are abj drical gonidia. c cylindrical gonidia with sprouts, from the blood of a caterpillar 
attacked by the Fungus; one extremity of @ is fixed in a blood-cell. £ extremity of a filiform gonidiophore which has grown 
out of the skin ofa caterpillar of Sphinx Euphorbiae killed by the Fungus and converted into a sclerotium. Magn. about 
400 times. 






as an example” The ascospores formed in the orange-coloured club-shaped 
stromata are ejected as narrowly filiform or rod-shaped bodies divided by transverse 
walls before they leave the ascus into a row of many shortly cylindrical secondary. 
spores, which are at least 160 in number. When placed in any fluid, they usually 
separate from one another, swell slightly, become rounded in shape and then put out 
germ-tubes (Fig. 165, 4); sometimes, but not always, the spores become partially 
united together again by means of short connecting tubes before they germinate. 
Germination takes place on the surface of the skin of a caterpillar if it is only slightly 
moist. The germ-tubes penetrate at once, and at any part of the surface, into the 
chitinous skin of the insect. Here they enlarge into somewhat stouter fungal hyphae, 
which ramify and in the simplest case make their way by a sinuous course into the. 
deeper layers of the skin, at length reaching the inner surface and insinuating them- 
selves between the bundles of muscles and lobes of fatty substance of the creature. 

1 As cited on page 273. 
® Bot. Ztg. 1867, p. 1, and 1869, p. 590. 
Bb 2 
