THE OCCURRENCE OF RICKETTSIA-LIKE MICROOR- 

 GANISMS IX ADULT "LOCUSTS" (TIBICEX 

 S EPTEXDECIM LI N N . ) . 



E. V. COWDRY. 

 Roi :TLTE FOR MEDICAL RESEARCH, NEW YORK, X. Y. 



\Yhile attempting to extend some studies already made dealing 

 with the distribution of Rickettsia in insect tissues 1 a number of 

 "lo ed in the vicinity of Teaticket, Massachu- 



:;d wei. lined microscopically at the Marine Biological 



Laboratory. Eleven out of 50 of these specimens, or a little ovt-r 

 20 per cent., wen- found to he heavily infested with peculiar micro- 

 organiMii.s which it is the purpose of this note to describe briefly. 



In si/e they resembled Rickettsia in being somewhat smaller 

 than must bacteria. After alcoholic fixation and coloration by 

 1 1 they measured from 0.2 to 0.3 micron in diam- 



ainl f _ to 1.5 microns in length, with average dimensions 



df <>._ IA i ii micron. They were usually straight with bluntly 

 rounded ends and were sometimes arranged in pairs (Figs. 1-3). 

 Like Ricki-'.i.<ia. these microorganisms tended to be stained red by 

 this technique; hut unlike Rickettsia. they were somewhat resistant 

 i.. decoloi . by Gram's method this was however a matter 



in quality rather than one of distinct difference (Fig. 

 restricted in distribution to the lumina of the ali- 

 ntary tracl and Malpighian system that is to say to two loca- 

 tions in which Rickettsia are very frequently met with. The 

 manner in which they were seen to be applied in thick masses 

 u| on the epithelial surfaces was also suggestive of Rickettsia (Fig. 

 2). They were seldom observed within cells. In infested " lo- 

 custs " the alimentary and Malpighian systems were not uni- 

 lormly invaded throughout their whole extent. In serial sections 

 it was ;i common experience to observe perfectly normal tubules, 

 devoid of microorganisms, and then suddenly to encounter large 

 numbers of them. In these areas the lining epithelium showed no 



i Cowdry. E. V.. /. /:>/. .\fcd., 1923, XXXVII., 431. 



15 



