95 
the growth on the insect, and consequently are not prepared to 
say that continued cultivation oq an inanimate medium might not 
finally diminish the virulence of the fungus parasite; but, on the 
other hand, we have no very good reason to suppose that this will 
prove to be the case; and I have no doubt that by a properlv 
guarded procedure these artificial cultures, which can easily be 
made in almost unlimited quantity, may be utilized for a dissemi¬ 
nation of the spores of these insect diseases with great advantage 
in convenience, expedition, and economy of operation. (Compare 
Nos. 3, 4, and 5 with No. 54; also, No. 71 with No. 70, up to 
July 6.) 
11. The history of experiment No. 1 and its derivatives shows 
beyond question the possibility of doing excellent work on chinch- 
bugs with fuogus of this disease derived from other insect species. 
It is probable that many cases of its apparently spontaneous ap¬ 
pearance among chinch-bugs are to be traced to such sources of 
infection. It was upon this ground that fragments of thirteen-year 
locusts profusely covered with Sporotrichum were distributed this 
summer, together with chinch-bugs previously exposed to infection, 
for experimental use by farmers. 
12. A comparison of the infection experiments made on chinch- 
bugs with those made on cabbage worms (see subsequent list) shows 
clearly the very much greater susceptibility of the latter to Sporo¬ 
trichum attack—a fact due possibly to their thinner skin and 
more juicy substance. Living and dead cabbage worms were in¬ 
fected with equal readiness if the air was kept moist. The spores 
started quickly on any part of the body, the growing hyphae pen¬ 
etrating the skin in one place seemingly as freely as in another. An 
external development of the fungus commonly became noticeable 
on the second day, as in artificial cultures. Cabbage worms were 
frequently, but not invariably, turned a dull red color by the 
growth of the Sporotrichum. In one experiment, which differed 
fr >m the others by the omission of the layer of moist sand on 
the bottom of the dish in which the larvae were confined, this 
raspberry color was the only external evidence of successful infec¬ 
tion with the Sporotrichum, no external growth appearing—a fact 
probably to be attributed to the comparative dryness of the air. 
.13. This is the place to make mention of certain experiments 
with the infection of insects in the laboratory which resulted in 
unusual developments of Sporotrichum globuliferum , illustrated by 
figures accompanying this report (Plate VII.) With the exception 
uf the two growths from June beetles (Fig. 5 and 6), whose bo¬ 
tanical characters are identical with those of Sporotrichum, these 
igures were made from growths resulting from the infection of 
iving insects with spores from cultures made by us. The identity 
uf these Isaria forms was further verified by raising the common 
Botrytis form from each of them on agar.* 
-sh a ped growths figured on this Plate (Pig. 1-4) had a general resemblance to Cordvceps; 
Iverthe Inrf&ce^^ tUft8 ° f femle hyphae ’ bearin S profusely the usual heads of Botrytis spores all 
