June 26, 1919] 



NATURE 



325 



The refulgent patches of feathers are absent in some 

 groups of humming: birds, such as the "Hermits," 

 but these have the habit of frequenting the gloom of 

 the forests, and of catching the small insects that 

 form their food from on, or beneath, the foliage, and 

 these habits explain their absence. 



Perhaps this suggestion may lead others to investi- 

 gate the facts from a more strictly scientific view- 

 point. H. J. Charbonnier. 



Rose Cottage, Olveston, nr. Bristol. 



The Stinging Instinct in Bees and Wasps. 



It is almost impossible to irritate a worker wasp 

 or bumble-bee to the pitch that it will fly to attack, 

 except when it is defending its home. The queen 

 wasp or bumble-bee will not even defend her home. 

 If she is disturbed when the nest is in a very early 

 stage, She deserts it. When it is in an advanced 

 stage she will return to it afterwards. Worker honey- 

 bees are also disinclined to attack except when de- 

 fending their home But in beating off a threatening 

 bee as one walks through the apiary, one is very 

 likely to get stung. The readiness to attack and the 

 force of the attack are in proportion to the popula- 

 tion of the colony. As soon as the nest or hive is 

 removed, the returning bees or wasps that hover 

 around the old place, vainly searching for it, cannot 

 be induced to attack. 



But recently I took a hive of bees out of its winter 

 case and carried this case, which had a few of the 

 bees crawling around the flight-holes, to a distant 

 part of the apiary. Two hours later some of these 

 bees still remained on the case, and I started to brush 

 them off. They flew up angrily at me and gave me 

 several stings. Hive-odour is evidentlv an important 

 factor in the stimulation of the stinging instinct. 



F. W. L. Sladen. 



Ottawa, Canada. 



The American Astronomical Society. 



Some of your readers may have seen the erroneous 

 statement in the issue of Science for May 9, 1919, 

 p. 446, stating that at the next meeting of the 

 American .\stronomical Society there would be repre- 

 sentatives from the observatories of Greenwich, 

 Oxford, Cambridge, Vienna, and Potsdam. This 

 statement was copied from a student publication, 

 which confused the coming meeting with the attend- 

 ance at previous meetings of the society. There will, 

 of course, be no German or Austrian astronomers at 

 any meeting of the society in the near future. 



Joel Stebbins (Secretary). 



Urbana, Illinois, June 11. 



GRAIN PESTS AND THEIR 

 INVESTIGATION.^ 



A CONSIDERABLE number of different in- 

 sects and mites occur in flour and 

 stored grain, some of which bring about 

 serious damage, while others are of com- 



> Royal Society, Grain Pests (War) Committee. Report No i., May, 

 1918. (i) Introfliictory Note. By the Chairman of the Committee. (2) 

 Report on the Effect of .\irtight Storage upon Grain Insects. Part i. By 

 Prof. A. Dendy. Report No. ii., 1918. (1) Bionomic, Morphological, and 

 Economic Report on the Acarids of .'^tored Grain and Flour. By Prof. R. 

 Newstead and H. Muriel Duvall. (2) Appendix i. By Prof. J, M. beattie. 

 (3) Appendix ii. By A. K. Hnmjihries. Member of the Royal Commission 

 on Wheat Supplies. Report No. iii., November, igi8. (i) Report on the 

 Effect of Air-tieht Storage upon Grain Insects. Part ii. By Prof. A. 

 Dendy and H. D. Elkington. (2) Experiments with Two .Secondary Grain 

 Pests, showing their Inability to Attack Sound Wheat. Bv Prof. A. Dendv. 

 <3) Observations on the Attraction of Certain Grain Beetles,^ especially 

 Weevils, by Water. By Prof. A Dendy. Memoranda Nos. i.-iii. Issued 

 January 24, 1918. 



paratively little economic importance. Up to 

 the year 1917 very little had been done in this 

 country with the view of determining the best 

 methods for dealing with grain pests. No trust- 

 worthy estimates were available as to the actual 

 damage sustained by cereal crops while in stor- 

 age, although there is abundant evidence that 

 material injury is incurred to both wheat and 

 maize, either before or after its arrival in Britain. 

 In June, 1916, the Council of the Royal Society, 

 as the result of a correspondence with the Board 

 of Agriculture, appointed the Grain Pests Com- 

 mittee for the purpose of investigating the rela- 

 tive importance of grain insects, suggesting 

 measures for combating them, and inquiring into 

 the extent of the losses sustained. The Com- 

 mittee included Mr. J. C. F. Fryer (Board of 

 Agriculture), Mr. O. E. Robinson (representing 

 the milling trade), with Prof. Herdman as chair- 

 man. Representatives of the Liverpool grain 

 trade and of the Incorporated National Associa- 

 tion of British and Irish Millers were also added. 

 Direct relations with the trades concerned were 

 established, and problems observed in the mills 

 and warehouses were investigated both on the spot 

 and in the laboratory. It was decided to divide 

 the work between several institutions in London 

 and the Liverpool L^niversity, while further work 

 was delegated to the zoological laboratory at 

 Oxford. 



The results obtained by the Committee's investi- 

 gations are being issued by the Royal Society in 

 two series : (i) Memoranda mainly of a provisional 

 nature; (2) reports of the detailed investigations. 

 Three reports and the same number of memor- 

 anda have appeared up to date. The first report, 

 by Prof. Dendy, deals with the effect of air-tight 

 storage upon grain insects. The earlier belief 

 that grain weevils are almost independent of ven- 

 tilation, and can live indefinitely in tightly closed 

 vessels, is not borne out by Prof. Dendy 's experi- 

 ments, in which hermetically sealed vessels were 

 used. By enclosing Calandra granaria and C. 

 oryzae in hermetically sealed vessels containing 

 wheat, the carbon dioxide evolved was observed 

 to have a lethal effect upon the imprisoned insects. 

 It was found that within the limits of a wide range 

 of conditions as to temperature, moisture, and 

 degree of infestation hermetical sealing is a very 

 effective method for dealing with the weevil prob- 

 lem. The time taken to bring about the lethal 

 effects appears to depend chiefly upon the relative 

 volume of air present. In practice it is, there- 

 fore, of first importance to ascertain that hermet- 

 ical sealing of the silos or other receptacles is 

 effectively carried out. 



The greater part of the second report is by 

 Prof. Newstead and Miss Duvall on the Acarids 

 of stored grain and flour. The most important 

 sf)ecies concerned is Aleurohiiis farinae, which is 

 not infrequently accompanied by the predaceous 

 mite Cheyletus eruditus. An excellent account of 

 the structure and bionomics of the latter species 

 is given : the authors express doubt whether it is 

 ever suflficientlv abundant in Nature to be effective 



NO. 2591, VOL. 103] 



