11” 
one for investigation, and should undoubtedly be most thoroughly 
studied from every point of view. 
THE CONTAGIOUS DISEASES OF THE WHITE GRUBS. 
The native contagious diseases of the American white grubs are 
not, so far as known, encouraging subjects for practical use in the de- 
struction of these insects; but certain other insect diseases, due to para- 
sitic fungi capable of artificial cultivation, offer a more promising re- 
source. Numerous experiments have been made in recent years in 
France with a native fungus parasite* of the European larva of Melo- 
lontha vulgaris (already frequently referred to as the agricultural equiv- 
alent of our species) which have been carried so far by Prof. A. Giard 
as to lead to the artificial cultivation of this fungus on a large scale, 
and its sale to farmers as a specific for that insect. 
Experiments with this fungus for the destruction of larvae of Lach- 
nosterna and allied American genera were made in my laboratory in 
1892, and similar and still more extensive experiments were made with 
two other species (Isaria leprosa and Sporotrichum globuliferum) oc- 
curring spontaneously in America. This work was done under my own 
immediate supervision by an assistant, Mr. John Marten, from whose 
report I take the following statement of methods and results: 
Two culture tubes of Botrytis tenella were obtained in 1892 from 
a Parisian firm of chemists, who offered the spores of this fungus in 
glass tubes for sale; and another was received directly from Professor 
A. Giard. March 31, 1892, fifty grubs taken from a rotten oak log— 
most of them Polymechus brevipes and the remainder Serica vesper- 
tina—were thoroughly dusted with a portion of the contents of one of 
these tubes, and were then placed in an earthen dish with a quantity of 
the rotten wood. A check lot was established under similar conditions, 
but not dusted with the spores. The first effect of this treatment was 
observed April 6, when a single larva each of Serica and Polymeechus 
was found dead, the latter with flabby thorax and the abdomen some- 
what hard. This lot of larvae was examined at intervals of two days, 
and April 8 one more was found dead, April 10 sixteen, on the 12th 
seventeen, on the 14th one, on the 16th three, on the 18th four, and, 
finally, May 2, sixteen more—making forty-nine in all. 
Infection by this fungus is unmistakably indicated by a pale pink 
tint of the dead larvee, deepening to a definite rosy color, which disap- 
pears, however, with the development of spores upon the surface of the 
grub. This characteristic color was shown by twenty of the above larve, 
the first exhibiting it April 8. It was noticed that the Serica larve, 
although seemingly affected like the others, did not change color in 
this way. An external mycelium was first shown April 16, on a grub 
which had died on the 8th and had then been transferred to damp sand 
and covered with a bell jar. Others showed this external growth on the 
18th and 20th, while spores first appeared April 26. From such spores 
successful cultures were made in test tubes of agar-agar, the culture 
medium assuming the deep red color to which this fungus gives rise. 
Proof was consequently complete of the destruction of at least a con- 
siderable number of these grubs by a thorough infection with spores of 
* Botrytis tenella or Isaria densa, as it is variously called by different authors. 
