io8 



NA TURE 



[NoVEMliER 25, 1909 



said : — " It is obvious, if malaria is due solely to the bites 

 of anopheles mosquitoes, that the extirpation of these 

 mosquitoes will abolish malaria. The continuous use of 

 quinine, even for a short time, is inconvenient, unpleasant 

 to the individual, and difficult to carry out among a com- 

 munity. It is therefore evident that the best way to get 

 rid of malaria is to destroy the mosquitoes. The only 

 questions are, Can it be done? and, if it can, At what 

 cost? It has been successfully done at Ismailia, but in 

 conditions which were extraordinarily favourable, such, as 

 I fear, occur very rarely, if they occur at all, in India." 



Colonef Leslie then referred to the operations against 

 mosquitoes conducted at Mian Mir by Captain James and 

 Lieut. Christophers. The latter reported that a distinct 

 effect was produced upon the malaria of troops and on tfie 

 indemic inde.K of the bazaars. This was, however, only 

 evident in the beginning of the fever season, and could 

 not be maintained. The failure of the operations appeared 

 to be due to the passage of adult anopheles into the area 

 from without. All the Mian Mir experiment showed was 

 that success in operations against mosquitoes is not so 

 easily gained as some people say. Where drainage is per- 

 fect, as in the case of Ismailia, the inhabitants can 

 exterminate mosquitoes with little trouble ; but where 

 drainage is non-existent or bad, as at Mian Mir, it is 

 practically impossible, by any means at present within 

 their reach, for the inhabitants to destroy the mosquitoes. 



After dealing with the question of prophylaxis by 

 quinine, Colonel Leslie proceeded to formulate a scheme 

 for a permanent organisation to deal with malaria in 

 India, viz. a committee in each province of three or more 

 members to obtain information and supervise local 

 inquiries, and perhaps to control the distribution of quinine. 

 Each provincial committee would delegate one of their 

 members to a'.tend a meeting of a general committee in 

 Simla, this general committee consisting of the provincial 

 delegates, the Sanitary Commissioner, representing the 

 Government of India, with Major James as secretary. The 

 Government of India would .ippoint a scientific committee, 

 and a certain number of workers would be under the 

 scientific committee, and when necessary workers might be 

 deputed to serve under the provincial committees. 



Major James, I. M.S., introduced a discussion upon the 

 distribution of malaria in India, and dwelt upon the 

 necessity for an investigation similar to that which Captain 

 Christophers made in the Punjab, which should be begun 

 in every province. He concluded that there are not 

 extensive areas in India in which anti-malaria measures 

 are urgently required ; he doubted if there were more than 

 half a dozen considerable areas in the Madras Presidency 

 which would come within this category. 



Captain S. R. Christophers, I. M.S., read a paper on a 

 new statistical method of mapping epidemic disease, with 

 special reference to malaria, and confined himself to a 

 discussion of the returns of the Punjab. He suggested 

 that in each district a list of the more unhealthy paraos 

 (rest camps) could be maintained, and operations com- 

 menced upon e.ach in turn with a view to (i) destroy 

 mosquitoes and larva; and get rid of their breedinf^ "round : 

 (2) render the wells mosquito-proof; (■\) issue quinine free 

 to the local inhabitants, and to place it at all times within 

 their reach free of cost. These operations should rpsult in 

 Ifssening the infectivity of such places. Captain 

 Christophers also read a paper on malaria in the Punjab, 

 in which he discussed quinine prophylaxis. 



Major Chaytor White, I. M.S., considered that the re- 

 commendations of oast malaria conferences are costly, and 

 almost prohibitively so, if undert.aken annunllv. More 

 should be done in the propagation of fish which prey on 

 mosquito larvae. 



Papers were also read by I.ieut.-Colonel Thornhill, on 

 malaria in cantonments ; by Major James, on problems 

 relating to the use of quinine; and Major Wilkinson 

 brought forward a revised scheme for the distribution of 

 quinine by Government. 



.'\t the termination of the conference various conclusions 

 and recommendations were drawn up under the following 

 main headings : — (i) scientific investigation ; (2) the agency 

 by which investigations should be made ; (^^ practical 

 measures : (a) extirpation of mosquitoes ; (b) quinine treat- 

 ment and prophylaxis ; (c) education ; (ci) finance. 

 NO. 2091, VOL. 82] 



ECONOMIC ENTOMOLOGY IN THE UNITED 



STATES. 

 1\/T ATLE trees grown in the United States are liable to 

 ,, severe injury from defoliation by caterpillars. In 

 addition to the fall web-worm (Ilyphantria cunea, Dru.) 

 and tussock moth caterpillar (Hcmerocampa leucostigma, 

 Dru.) there is a common and troublesome species known 

 as the green-striped maple-worm {Anisota rubicunda, 

 I'ab.), which attacks maples of all kinds, and feeds 

 occasionally on box-elder and oak. In a bulletin recently 

 issued by the United States Department of Agriculture 

 Bureau of Entomology, the latter pest is described in some 

 detail by Messrs. Howard and Chittenden. In another 

 publication they describe the leopard moth (Zeuzeni 

 pyrina. Fab.), the larvae of which cause severe injury to 

 many deciduous trees in northern New Jersey and eastern 

 New York. It has been successfully combated in the 

 public parks of New York City by injecting carbon di- 

 sulphide into the larval burrows in the bark. Mr. 

 Chittenden describes the rose-chafer (Macrodactylus sub- 

 spinostis, Fab.), a long-legged beetle of a light yellowish- 

 biown colour, which appears suddenly and in vast swarms 

 in certain years, usually towards the middle of June in 

 the northern States and about two weeks earlier in the 

 southern, overrunning vineyards and orchards, nurseries 

 and gardens. In about a month or six weeks from the 

 time of their first arrival, generally after they have done 

 a vast amount of damage, the beetles disappear as 

 suddenly as they came. No successful means of com- 

 bating them is yet known, the difficulty being that any 

 process, to be successful, must be applied almost con- 

 tinuously. 



The control of the pear-thrips (Euthrips pyri, Daniel) 

 has been for several years the principal problem confront- 

 ing the growers of deciduous fruits in portions of central 

 California. This insect, on account of its mode of attack 

 and habits, has presented unusual difficulties in control. 

 .Adults emerge from the ground in late February and early 

 March, just when most trees are breaking into bloom. 

 Kggs are usually deposited in the blossom, fruit stems, 

 and leaf petioles. The larva;, after hatching out, feed 

 for two or three weeks, then drop to the ground, where 

 they form a tiny protecting cell, within which they re- 

 main during the rest of the year. The pupal changes take 

 place within this cell in the ground during October, 

 November, and December. As measures of control, Mr. 

 Dudley Moulton recommends winter cultivation followed 

 by March and April spraying with tobacco extract. 



The life-history of the greenhouse thrips (Heliothrips 

 haeinarrhoidaUs, Bouch^) is described by Mr. H. M. 

 Russell. The damage caused by this insect is confined to 

 the foliage of ornamental plants. Adults and larvae both 

 obtain their food by puncturing the epidermis of the leaf 

 with their sharp mouth-parts and sucking out the sap. 

 Fumigation with nicotine or with hydrocyanic acid gas 

 were found to be effective methods of control. 



Mr. A. L. Quaintance, who is in charge of deciduous 

 fruit insect investigations, describes a new genus of 

 -Aleyrodida'. Paraleyrodcs (alenrodicus) pcrscae, Quaint- 

 ance, found on orange trees and other plants in Florida. 

 The adult is buff or pinkish in colour, and marked with 

 white. The wings are whitish and lie almost flat along 

 the dorsum, but do not meet along the middle line. A 

 large amount of flocculent white wax is secreted over the 

 leaf surface in the depressions in which the sluggish adults 

 rest. From the same section of the Bureau is issued a 

 description, by Mr. Hammar, of the cigar-case bearer 

 (Coleophorn (letcherella, IF-crnald), which damages the 

 foliage and fruit of apple and pear trees. The name is 

 given because of the curiously .shaped cases, resembling 

 cigars, made by the larvae. Arsenical sorays were found 

 effective in keeping it down. Messrs. Foster and Jones 

 publish some additional observations on the lesser apole- 

 worm (Enarmonia prnnivora, Walsh), which is prevalent 

 throughout the apple-growing district east of ^he Rocky 

 Mountains. Late broods do a considerable amount of 

 damage in autumn, and some of the larv.-u work in th" 

 fruit for weeks after the crop is harvested. The methods 

 adopted for keeping down the codling moth have, so far, 

 proved effective in checking serious injury by this pest. 



