ENTOMOLOGY

4,70 SANITARY ENTOMOLOGYcarcass to another, thus 'enabling the flies and other insects which visitfood to further distribute the germs. Proust found quantities of livingDerme8te8 'tJulpinu8 Fabricius in goat skins taken from anthracic animals.He found virulent anthrax bacillus in their excrement and alsoin their eggs and in the larvae. Heim also had occasion -to examine someskins which were suspected of having caused anthrax in persons engagedin handling leather. He found the larvae of Attagen'U8 pellio Linnaeus,A nthren'U8 mU8eorum Linnaeus, and Ptinus also fully developed insectsof the latter species on the skins. All these insects had virulent anthraxbacillus (spores) on their bodies and in their excreta.The greater proportion of the cases of beetle transmission of diseaseare those in which the beetle serves as an intermediate host of a parasiticworm. In most of these cases the beetle larvre are found in excreta. TIreyingest the eggs of the worms and the transformation takes place withintheir bodies. The worms are then eaten by animals and the infection iscarried on. Since Doctor Ransom, in his lecture, has summarized 0.11 ofthe evidence, it is unnecessary to repeat at this time.We are not apt to associate the transmission of prant diseases byinsects but the cases are strongly analogous. Just recently F. B. Randhas demonstrated the transmission of cueurbit wilt, which is caused byBacillus tracheiphilu8, by means of the cucumber beetle, Diabrotica 'tJittataFabr. He has found that the beetles take up the bacillus in eatingan injured leaf and has been able to demonstrate the presence of thebacillus in the body of the insect by dissection and culture with subsequentinoculation. He has conclusively proven that the disease can betransmitted only by means of this and closely related beetles. He hasfound also that the normal bacillus content of the abdomen may, in alarge proportion of cases, destroy the wilt bacillus. It is quite probablethat infection in this case is similar to that caused by the house :By, inthat the infected excreta come in contact with the recently eaten surfacesof the leaf as the beetle moves forward.It has been found that beetles can transmit mosaic disease of tobacco.It is not at all out of the way to expect that we will find ultimately asimilar transmission in this case and in many other plant diseases.LIST OF REFERENCESCastellani, A., and Chalmers, A. J., 1915.-l\fanual of Tropical :i\{edicine.Cornelius, H. B., 1919.-Indian Med. Gaz., vol. 54, No. ~,pp. '7!e, '73.Cornwall, J. W., 1916.-Indian JOUI'D. Med. Research, vol. 3, pp. 5fl-5'7, and 540-55'7.Ellingham, E. H., 1914.-Tr. Ent. Soc. Lond., 1918, pt. 8, p. 423.