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The readiness with which this Bacillus is cultivated artificially 
and the apparent deadliness of its attack make it a very prom¬ 
ising subject for experimental investigation, and it is conse¬ 
quently much to be desired that if it be again encountered in 
this or any other insect species, it may be thoroughly investi¬ 
gated from the practical point of view. 
The following description of the Bacillus itself and of its mode 
of growth on agar and in culture fluids will serve for its identi¬ 
fication wherever found. 
Bacillus rufans, n. sp.* 
Oval or short-cylindrical to rod-like, very variable in shape 
and size, often 1 to 5 micros long and .5 to 1.5 micros wide, 
free ends rounded; occurring singly, in pairs or in rods of three 
or four segments; sometimes slowly motile, usually not flagel¬ 
late; aerobic; non-liquifying, chromogenic; pathogenic in insects. 
The various liquid and solid media, as well as the tissues of 
affected insects, are diffusely tinged with red. The color spreads 
uniformly throughout the substances, which at first become 
yellowish, then, during two or three days, gradually deepen to 
orange and finally to dark blood-red. The growth on agar and 
on gelatine is smooth, shining, slightly elevated, more abundant 
upon the moister portions near the bottom of the tube, brown¬ 
ish white with scattered specks or dots of deep orange, usually 
aggregated in small blotches, the whole growth finally becom¬ 
ing a dirty cream color. Bouillon becomes tinged first near the 
surface, and the color gradually extends to the bottom, with a 
rather distinct line of separation from the still uncolored deeper 
material. A fragile white or slightly stained pellicle forms, but 
this readily breaks up and settles to the bottom as a loose 
precipitate. The organisms themselves are white. They readily 
stain with ordinary aniline dyes. The staining is sometimes 
solid throughout, but often, especially in the insect fluids, there 
is a broad central band of white. In a slide from an old fluid 
culture many spore-like forms occur. These appear like the 
ones with only the ends of the cells stained, except that the 
differentiation is more marked, and they are somewhat swollen 
in the central portions, becoming broadly, instead of rather 
narrowly, oval, as in other cases. Sometimes the rod-like forms 
have irregular dots of white (vacuoles). 
Growth takes place at the ordinary temperature of the room, 
but not rapidly. Other temperatures were not tried. 
I have discovered no insect enemy of this species, but Dr„ 
Bilev reports the rearing of two dipterous parasites of it; one 
from the larva and pupa, and one (a tachinid) from the beetle. 
* Prepared by Prof. T. J. Burrill, from my office notes and slides. 
