MICROORGANISMS IX LOCUSTS. 17 



Todd, and Palfrey: 7 'In every instance where careful study 

 has been made it has been found with the exception of the 

 rickettsia of typhus that the organisms pass down through suc- 

 cessive generations in the eggs." 



It is in connection with this possibility of hereditary transmis- 

 sion that further study of the microorganisms mentioned in this 

 note may be interesting, particularly since their hosts exhibit a 

 very unusual life history, some aspects of which have been made 

 the subject of recent contributions to the BIOLOGICAL BULLETIN 

 by Ilargitt 4 and by Hickernell. 8 The particular Massachusetts 

 brood, with which we are concerned, is possessed of a distinguished 

 ancestry. Marlatt " quotes a description of the first swarm noted 

 by settlers in H^I- in Moreton's words, as follows: 



" It is to be observed that the Spring before this Sickness, there 

 \\as a numerous company of Flics, which were like for bigness 

 unto J/'.jyfx or I'-.i.tnblc-Bees. they came out of little holes in the 

 ground, and did eat up the green things, and made such a constant 

 vrllin- n<.ise as made all the woods ring of them, and ready to deaf 

 the liearer> : they were not any of them heard or seen by the Eng- 

 lish in the country before this time: But the Indians told them that 

 M follow, and so it did . . . ." 



P.y citing this historic reference and by mentioning certain 

 points of resemblance between the microorganisms and Rickettsia. 

 the implication is not intended that the "locusts," or their para- 

 ire in any way associated with human disease. During the 

 it "locust" plague of 1868 and during every important re- 

 appearance of the insects before and since that time there have 

 been mam ts of the infliction of more or less serious stings. 



We ha\e ^<>od authority (Riley) for assuming, however, that 

 these stin-s are not caused by the "locusts" themselves but by 

 other insects, such as digger wasps, which are often prevalent at 

 the same time. 



- \V,.ll,;,cli. S. B., Todd, J. L., and Palfrey, F. \V., "The Etiology and 

 Pathology of Typhus." Harvard University Press. Cambridge, Mass., 1922, 



pages. 



8 Hickernell. L. M., BIOL. BULL., 1923, XLY ., 213. 



Marlatt, C. L. "The Periodical Cicada." Bull. No. 71, Bureau of En- 

 tomology, Washington, 1907, 181 pages. 

 2 



