195 



The exact relation between direction of dispersion and direction of 

 wind could not be determined because of the fluctuating wind condi- 

 tions experienced. There appears to be a tendency for M. domesiica 

 and C. macellaria mainly to follow the direction of the wind, but they 

 are shown to travel against it and at right angles to it as well. It is 

 concluded that under natural conditions the influence of moderate 

 winds on dissemination is not of great importance. 



The evidence gained justifies the conclusion that the passing of 

 vehicles along highways w^as not a dominating factor in the dispersion 

 of any species of flies in these tests. This does not mean, however, 

 that flies under other conditions may not be widely scattered by 

 artificial means. 



These tests show that the house-fly, screw-worm fly, and black blow- 

 fly spread rapidly for many miles. C. macellaria was recorded about 

 eight miles from the point of liberation in less than 24 hours, and ten 

 miles in less than 48 hours, after liberation. P. regina was recovered 

 about eleven miles away in less than 48 hours after release. M. 

 dornestica was recovered over six miles from the point of release in 

 less than 24 hours. Males as well as females of the principal species 

 used in these experiments may travel many miles. 



The maximum longevity of the marked flies after liberation as shoN\n 

 by the records of capture was : M. domesiica, 15 days ; C. nuiccllaria, 

 17 days; P. regina, 10-11 da^'s ; Ophyra aenescens, 6-8 days; 

 Sarcophaga spp., 11-12 days. 



While in the fourth experiment no marked flies were captured in 

 the more distant traps (about 17 mfles from the point of release), 

 it is the authors' belief that the limits of dispersion were not reached 

 in that test, and that where great numbers of flies are constantly 

 emerging the distance traversed may be much farther than the 

 maximum here determined. 



The facility with which flies travel many miles emphasises the import- 

 ance of the general apphcation of sanitary measures looking toward 

 the suppression of fly breeding. 



Davies (L. W.) & JoHxsox (W. B.). Notes upon the Occurrence of a 

 Twelve-day Fever of Dengue Group in Nigeria. — //. Trop. Med. 



& Hyg., London, xxiv, no. 14, 15th July 1921, pp. 189-193. 



The occurrence is recorded in the Northern Provinces of Nigeria 

 of a fever lasting about 12 da\-s and showing many similarities to 

 dengue fever. The evidence points to the probabilit}" of infection 

 by means of a biting insect, and the resemblance to dengue fever 

 would sviggest a mosquito. The seasonal occurrence of the disease 

 (July to October) corresponds to the period immediately after the 

 maximum abundance of Ctdex spp. Sand-flies {Cidicoides sp.) are 

 very troublesome at the same time. 



Edwards (F. W.). Diptera Nematocera from Arran and Loch Etive. — 



Scottish Nat., Edinburgh, nos. 111-112, 113-114 .\: 115-116, 

 March-August 1921, pp. 59-61, 89-92 & 121-125, 12 figs. 



This list includes the following Chironomids recorded for the first 

 time from Britain : Forciponiyia canalicidata, Goet., Atrichopogon 

 hamiferus, Goet., Dasyhelea diplosis, Kieff., D. polita, sp. n., Culicoides 

 guttidaris, Kieft"., C. heliophilus, sp. n., Psilohelea edentata, sp. n., 

 P. sociabilis, Goet., P. niiidnla, sp. n., P. perpusilla, sp. n., Palponiyia 

 nigripes, Mg., Clinohelea subsessilis, Goet., a.nd Bezzia tenebricosa, Goet. 



(4S86) p 2 



