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THE AGRICCTLTUKAL NEWS. 



September 17, 1910. 



INSECT NOTES. 



THE BRUSSELS CONGRESS OF 

 ENTOMOLOGY. 



An account of the proceedings of this Congi-ess is con- 

 tained in the London Times of August 10, 1910, from which 

 the particulars in the following article are taken 



The Congress was held from August 1 to 6, and included 

 a membership of 292, of which sixty-seven representatives 

 were from British Institutions, or w-ere British private indi- 

 viduals. Ths Imperial Department of Agriculture for the 

 West Indies was represented by its late Commissioner, 

 Sir Daniel Morris, K.C.M.G. 



In relation to the spread of disease by insects. Dr. E. 

 Blanchard, of Paris, gave a lecture on Medical Entomology, 

 in which special attention was drawn to the large part played 

 by insects, especially in the tropics, in the distribution of 

 disease. The lecturer dealt chiefly with the Anophelinae and 

 malaria, Stegomyia fasciata and yellow fever, Glossina spp. 

 and .sleeping sickness (trypanosomiasis). In connexion with 

 the last-mentioned of these, reference was made to the death 

 of Lieut. Tulloch, of the Army Medical Department, which 

 was caused by his being attacked by it when engaged in 

 investigations on it in West Africa. A matter of particular 

 interest is that definite relationship between these diseases and 

 the insects which carry them, makes the study of the latter 

 a subject for inclusion in the realm of practical medicine 



Several papers serve to illustrate the intimate connexion 

 that exists between entomology and agriculture. The first 

 of these was read by Sir Daniel Morris; it dealt with the 

 methods that are employed in the West Indies to prevent the 

 importation of insect pests into the various islands, with 

 special reference to the legislation in connexion with this. An 

 account of the work of this kind which has been done will be 

 found in the West Indian Bulletin, Vol. X, p. 197. An in- 

 structive description was given by Dr. G. H. Carpenter, of the 

 Royal (.'oUege of Science, Dublin, of the warlsle Hy {Hi/poderma 

 bovis) which lays its eggs on cattle, so that grubs are pro- 

 duced which enter the flesh and render it unfit for food. 

 (See A;/rindfural JVews, Vol. VIII. p. 170.) The conclusion 

 reached, .so far, was that the washes which have been suggest- 

 ed for employment against this pest are useless for the purpose 

 of its control. Dr. P>. S.MacDougall, of Edinburgh L'niversity, 

 gave an account of the damage that is done by a small beetle, 

 Galerucella lineola, to the osier beds in the Midland and 

 Western Counties of England. Arsenical sprays have been 

 found eifective against this, where the smaller-sized plants 

 are attacked. 



Numerous and interesting papers dealing with subjects 

 connected with pure entomology included those on ants and 

 their guests, and mimicry; and an account was given of 

 a recent Sw^edlsh entomological expedition to Kilimandjaro, 

 the results of which have been many and interesting. 



On the last day of the Congress, papers were read on 

 general subjects. In one of these, Mr. J. N. Howlett, F.E.S., 

 of the Imperial Agricultural Research Institute, Pusa, 

 described the difficulties of keeping collections of insects in 

 climates where there are sudden changes of temperature and 

 humidity, and came to the conclusion that .specimens could 

 only be protected, under such circumstances, from the 

 damage done by mites and moulds, by continual careful 

 attention. Dr. H. Skinner, an American delegate, gave 

 a brief account of the history of entomology in the LTnited 

 States during the last 100 years, insisting upon the great 

 value that entomological work had already shown, in refer- 

 ence to agriculture especially, in that country. 



At the final general meeting, an invitation was given for 

 the next congress to be held at Oxford, in 1912, and the 

 acceptance of this was agreed upon. 



HOUSE-FLIES AND DISEASE. 



A valuable article with the above title appears in 

 Nature for July 21, 1910. This deals, firstly, with the 

 history of the association of unhealthy conditions with flies, 

 pointing out that in 1871, Lord Avebury described flies as 

 'winged sponges spreading hither and thither to carry out the 

 foul behests of contagion'. Before this, it had been shown that 

 the house-fly and and the blow-fly were capable of transmitting 

 the anthrax bacillus, and in 1873 the possible dissemination 

 of cholera by flies was indicated. Laveran showed, in 1880, 

 that flies were able to carry the infectious discharge from 

 a disease of the eyes known as conjunctivitis, in Egypt. The 

 chief progress in the matter has, however, been made since 

 1886, when the micro organism causing cholera was obtained 

 from flies caught in wards where cases of that disease were 

 being treated. In the same year, the micro-organism of 

 consumption (tuberculosis) was found in the excreta of flies 

 from a room which had previously contained a sutt'erer from 

 the disea-se. In 1888, the important observation was made 

 that the typhoid bacillus was able to pass, in a condition in 

 which it was capable of producing the disease, through the 

 digestive organs of the fly. 



The article proceeds to a consideration of the incidence 

 of typhoid and enteric fever during the Spanish-American 

 and the South African wars, showing that, under the condi- 

 tions of sanitation of the camps, the spread of these diseases 

 is easily explained in the light of what is known about the 

 habits of the house-fly. The observation is made that, 

 although the insect may be almost sterile, that is free from 

 micro-organisms, when it emerges from the pupal case, yet it 

 quickly picks up infectious living matter. Evidence in 

 support of this is adduced by means of some experi- 

 ments by Giissow, which have not been published so far. 

 In one of these, thirty colonies comprising six species of 

 bacteria, and six colonies comprising four species of fungi 

 were obtained from a single fly, which was caught in the 

 living room of a house and allowed to walk over the surface 

 of material on which the organisms could develop. In 

 another, forty-six colonies comprising eight species of bacteria, 

 and seven colonies comprising four species of fungi, were 

 obtained in the same way from a fly caught in the open. 

 Finally, a'house-fly caught in a hou.sehold dust-bin yielded 

 similarly 116 colonies of bacteria comprising eleven species, 

 some of which were capable of producing disease, and tea 

 colonies comprising .-ix species of fungi. 



The eggs of the house-fly are laid preferably on 

 hor.se manure. The likelihood, however, of their being 

 deposited on almost any kind of filth makes it easy to 

 see what a potent factor the insects may become in relation 

 to the transmission of disease. This is of special importance 

 in view of a recent discovery by Faichne, to the effect that 

 larvae developed in infected material produce flies which 

 may carry the ty[ihoid bacilli in their digestive organs, and 

 that these bacilli may retain their power of causing the 

 disease for more than three weeks. 



The article concludes with an expression of the impor- 

 tance of flies as factors in the dissemination of disease, and 

 points out that, although these insects cannot be eradicated 

 from any given district, yet measures for their control, by 

 preventing their breeding as far as possible, are quite practi- 

 cable, and that the usefulness of these is bound to attain 

 a larger amount of realization in the future. 



