68 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



gator stated: "One can readily see the danger of our situation 

 if ants acted as carriers of pathogenic micro-organisms, for it 

 is absolutely impossible to keep them out of the house, and they 

 get into food in spite of our efforts." Two series of experiments 

 were performed to determine whether ants could carry Bacillus 

 typhosus, either in their alimentary tracts, or on the surface of 

 their bodies. It was found under certain conditions that infec- 

 tion of culture media could be brought about by allowing ants 

 artificially infected to come in contact with it. Referring to the 

 other experiments Dr. W. M. Wheeler makes the following state- 

 ments: 1 "The other series of experiments gave negative results, 

 for after dissecting ants that had been fed typhoid bacilli, neither 

 these nor any other micro-organisms could be cultivated from 

 the intestinal tract. From these results Darling proceeds to 

 draw an erroneous conclusion which can only be due to ignorance 

 of the anatomy and physiology of ants. He tested his ants for 

 formic acid and found that two of the species with which he 

 worked (Camponotus zonatus and Tetramorium guineense) con- 

 tained 2.1% of this substance, and he believed that because its 

 germicidal value is four times as great as that of carbolic acid, 

 the "ants may effectually sterilize bacteria in their food." Though 

 not definitely stated, it seems that Darling supposed the formic 

 acid to be secreted in the alimentary tract of the ant, which is, 

 of course, erroneous, and he seems to believe that this acid is 

 generally present in ants, whereas it is produced only by certain 

 genera and species." 



After all but one side of the subject has been touched. We 

 have dealt largely with insects in connection with diseases the 

 exact nature of which is unknown and with an eye to the future. 

 There remains the whole field of diseases in which insect agency 

 is established. There are the malarial mosquitoes, ticks, and 

 the house fly where the problem of control of disease is largely 

 if not essentially the control of the vector. Here are large and 

 immediate demands for entomological research. What may be 

 expected is shown by recent work on the house fly. The first 

 season it revealed a previously untried agent for the destruction 

 of the immature stages in manure that exceeds the substances 

 that had been used in cheapness, effectiveness, and in harmless- 

 ness to the manure as a fertilizer. 2 The second season this work 

 yielded a trap which promises to do away with the use of chem- 

 icals altogether under many conditions and results in chemotaxis 

 which will possibly be of great importance in the control of many 

 species. In the work on malarial mosquitoes similar progress is 



1 Wheeler, W. M. Am. Journ. Tropical Diseases, II, No. 3, 163. 



2 Cook, F. C., et al. Bulletin 118, Bur. Ent., U. S. Dept. Agric. 



