MICROBIAL DISEASES OF INSECTS Q2Q 



BACTERIAL SEPTICEMIA OF LARV.E OF THE LAMELLICORN.E 

 Bacillus septicus insectorum Krassilstschik 



HISTORY AND DISTRIBUTION. This disease occurred separately 

 and together with graphitosis previously described. 



SYMPTOMS. The septicemia produced in larvae of the Lamelli- 

 cornae by B. septicus insectorum is characterized by a uniform browning 

 of the body of the larvae. As death approaches, the larva shrivels up 

 and when dead is about half its natural size and is of a deep brown color. 

 During the progress of the disease, the larva ejects a very black, abund- 

 ant, viscous, semifluid substance from the anus which soils the ex- 

 tremity of the abdomen. 



CAUSAL ORGANISM. This bacillus is 1.2/1 to i.Sji long and from o.6ju to o.g/x in di- 

 ameter; often in pairs; long filaments not formed. Spores are characteristically dip- 

 lospores although isolated ones occur not infrequently. It shrinks very little when 

 stained by Gram's method. 



Gelatin is liquefied; subsurface colonies are decidedly lemon shaped, yellowish 

 brown, finely granular, surface of colony typically curled. Surface colonies are con- 

 centrically three-ringed, the interior opaque, the second ring more transparent, the 

 third very thin and finely granular. Saccate liquef action in gelatin stab; the gelatin 

 is blackened and has a very disagreeable odor. Spores are found in the sediment at 

 the bottom of the tube. Broth is made turbid in eighteen to twenty hours, no 

 pellicle, bad odor. 



METHODS OF INFECTION. Healthy larvae inoculated with B. sep- 

 ticus insectorum by placing cotton saturated with a broth culture on a 

 wound, died in most cases with typical symptoms. 



The sole habitat of these microbes before death is in the blood 

 system. 



BACTERIAL DISEASE OF THE GUT-EPITHELIUM OF Arenicola 



ecaudata, the Lug- Worm 

 Bacterium arenicola. Fantham and Porter.* 



HISTORY AND DISTRIBUTION. This bacillus was found in the lumen 

 of the gut and within the intestinal epithelium of specimens of Areni- 

 cola ecaudata obtained from Plymouth, England. This disease is not of 

 frequent occurrence. 



* Pantham, P. B. and Porter, A. Bacillus arenicolct, n. sp. t a pathogenic bacterium from the 

 gut-epithelium of Arenicola ecaudata. Cent. f. Bakt. I., Orig. 52, 1909, 320-334- 

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