90 



THE AGRICULTURAL NEWS. 



March 18. 19U. 



INSECT NOTES. 



THE ENTOMOLOGICAL RESEARCH 

 COMMITTEE. 



During 1909, the Colonial Office appointed a Committee 

 to cany out investigations in Economic Entomology in Tropi- 

 ■cal Africa, with special reference to the relation between 

 diseases, in man and animals, and ticks and insects. 



The Committee includes several eminent Entomologists 

 who receive and study the material sent in by the Committee's 

 collecting entomologists, and that sent in by the Government 

 Entomologists of the several African colonies, and also by 

 medical officers and others who collect. The results of these 

 studies are published as papers in the Bulletin, of Entomolo- 

 gical Resedvrh, published by the Committee, which has 

 appeared in four parts (Vol. I, parts 1-4), with a total of 

 319 pages. The separate parts have appeared as follows : 

 .Parti, April 1910: Part II, July 1910; Part III, October 

 1910; and Part l\, January 1911. 



There have been presented five papers dealing with 

 mosquitoes, their habits, life-historj' and distribution, giving 

 'accounts of the different stages of development; and in many 

 cases accompanied by figures from drawings and photographs. 

 Papers dealing with the blood-.sueking Diptera number six- 

 teen. These include studies of tse-t.se flies, which carry 

 sleeping sickness and diseases of cattle; of the gad flies or 

 horse flies of the family Tabanidae, which annoy animals by 

 their vicious biting, and notes on habits and distribution. 



Three papers have appeared on sleeping .sickness; one on 

 a sub-family of the Tachinidae, the larvae of which occur as 

 subcutaneous parasites of man; one on the fleas attacking 

 mice and rats; and one on the families of Acarina. 



The more strictly agricultural papers have been on fruit 

 flies (two), Coccidae (five), and Heniiptera injurious to 

 cacao (two). 



The notes on Coccidae are based on collections from 

 Uganda, forwarded by Mr. C. C. Gowdey, B.Sc, which have 

 been studied by Mr. R. New.stead. These are of scientific 

 interest, since they contain several new species; and small 

 Hymenopterous insects, which are stated to be fairly abund- 

 ant, occur as parasites of the Uganda scale insects. 



The notes on Hemiptera injurious to cacao include an 

 account of a species of Helopeltis from the Gold Coast, which 

 occurs as a pest in certain localities. The mosquito blight 

 of tea in India is due to a species of this genus {Helopeltis 

 theivora), which rendered large areas of tea plantations in 

 Northern India unproductive. The injury is caused by the 

 punctures of the insect, made in feeding. These cause many 

 young pods to die, and often injure the older pods to such 

 an extent that, although they survive on the tree until they 

 reach maturity, the seeds are worthless. 



Another Hemipterous in.sect injurious to cacao on the 

 Gold Coast is the cacao bark sapper {Salillienjclla Iheoh-oma), 

 with which is often associated a nearly allied species {Sahl- 

 Ijeryflla siiiifiilaris). These insects are reported as destrojing 

 cacao trees in certain localities. The injury to the trees 

 results from the punctures in the bark made by the insects 

 with their sucking mouth parts while feeding. Experiments 

 indicate that spraying with kerosene emulsion, at a time when 



the immature insects are abundant, is an efficient and prac- 

 tical measure. 



A paper by I)r. W. M. Graham on West African fruit 

 flies (Trypetidae) states that these pests belong to two 

 genera; Ceratitis, of which nine species have been recorded, 

 and Dacus, of which eleven species are known. Very little 

 .seems to be descrilied of the habits and food plants of most 

 of these .species, but they are all liable to prove serious pests 

 to fruit cultivations. 



The remedies suggested are the destruction of all fallen 

 fruit and the use of the poisoned sweet mixture which has given 

 such good results in Cape Colony. This is prepared by mix- 

 ing: sugar 21 lb., arsenate of lead (paste) 3 oz., and water 

 4 gallons, and is applied liy being sprayed on the foliage of 

 infested fruit trees. The adult flies feed upon this mixture 

 and are killed. 



In the second paper on fruit flies, Mr. E. E. Austen des- 

 cribes a new genus and two new species from Uganda. It is 

 expected that these insects will prove to be pests of fruit but 

 nothing is known of the life-history and habits. 



Certain of the statements with regard to the yellow fever 

 mosquito, Stegomi/ia fascinta, which are found in the paper 

 on the Prevalence, Distribution and Significance of Stegomyia 

 tasciatii, F. (S. calepus, Mg.) in West Africa, by Sir Hubert 

 Boyce, may hs of interest. Sir Hubert Boyce visited the 

 West Coast in I'.UO, to investigate the conditions existing in 

 connexion with an outbreak of yellow fever. He found 

 Stegomyia abundant in many towns, more abundant in fact 

 than in any of the localities visited by him in the West Indies 

 and Central America. The yellow fever mosquito was found 

 breeding in both pure and foul water, liut always in the 

 vicinity of human habitations. Mosquito larvae do not have 

 a purifying effect on water in which they occur, as is some- 

 times supposed, but on the contrary tliey contaminate pure 

 water, and probably increase the contamination in foul. 



The statements in regard to the length of time spent in 

 the several stages are of interest. It lias been found that the 

 Stegomyia eggs collected in Manaos were kept practically 

 dry for from forty-five to forty-seven days, and that when 

 these were placed under suitable conditions in England, 

 they hatched in from six to twelve hours: the larval sta^e 

 occupied nine days, the pupal stage three days, the com- 

 plete cycle thus occurring in from twelve to thirteen days 

 after the eggs were placed in conditions suitable for their 

 development. 



It has been stated, also, that the eggs of Stegomyia are 

 laid at the edge of the water and not actually in or on it. 

 Accordingly, if a period of dry weather ensues directly after 

 the deposition of Stegomyia eggs, these may remain dormant 

 until submerged by the rise of water due to rains, and then 

 hatch. 



The length of time that an infected female yellow fever 

 mosquito may live before depositing eggs is sometimes con- 

 siderable, and this may often account for the sporadic 

 appearance of yellow fever long af tei- tlie latest known cases 

 have occurred. 



The influence of infected immunes in a district where 

 Stegomyia is present and yellow fever is at the time absent, 

 is also indicated, by acting as reservoirs of j'ellow fever from 

 which new ca.ses originate. Mosquitoes may become infected 

 by biting such persons, and then give rise to new cases of 

 yellow fever. 



This review of thecontent* of tlir numbers of the journal 

 published so far by the Committee of Entomological Research 

 should serve to show the wide scope of its work, and the way 

 in which its labours are assisting in the opening up of new 

 countries for the practice of scientific agriculture. . i 



