— 133 
The readiness with which this Bacillus is cultivated artificially and 
erhe apparent deadliness of its attack make it a very promising subject 
_ for experimental investigation, and it is consequently much to be de- 
sired that if it be again encountered in this or any other insect species, 
- it may be thoroughly investigated from the practical point of view. 
3 The following description of the Bacillus itself and of its mode of 
growth on agar and in culture fluids will serve for its identification 
wherever found. 
7 
WOE Aes Peay Fre? pee epg 
Bacillus rufans, n. sp.* 
Oval or short-cylindrical to rod-like, very variable in shape and 
size, often 1 to 5 microns long and .5 to 1.5 microns wide, free ends 
~ rounded ; occurring singly, in pairs or in rods of three or four segments ; 
sometimes slowly motile, usually not flagellate ; aérobic; non-liquefy- 
. ing, chromogenic ; pathogenic in insects. 
3 The various liquid and solid media, as well as the tissues of af- 
fected insects, are diffusely tinged with red. The color spreads uni- 
' formly throughout the substances, which at first become yellowish, then, 
during two or three days, gr adually 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, brownish white with scattered specks or dots of deep 
orange, usually aggregated in small blotches, the whole growth finally 
becoming 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 differ- 
entiation is more marked, and they are somewhat swollen in the cen- 
tral 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. 
T have discovered no insect enemy of this species, but Dr. Riley 
reports the rearing of two dipterous parasites of it; one from the larva 
and pupa, and one (a tachinid) from the beetle. Professor H. Garmant 
notes the occurrence of small numbers of predaceous beetles and larve 
| in summer and fall with young root worms in the earth. He also men- 
tions some internal parasites OF the imago——Gregarine: and nematode 
‘worms. 
s Notwithstanding the abundance of the adult Diabrotica and its 
4 general distribution upon a great variety of plants, it seems but little 
3 noticed by birds. It has occurred but once in my own studies of the 
ee ee 
Rei * Prepared by Prof. T. J. Burrill, from my office notes and slides. 
; Psyche VOle Vile Clsoi), p 
