272 tnsecta. 



14 hours at 76,2** Fahr., while in the colder climate of Ohio it lasted 4 dayg 



15 hours at 76, 85'' Fahr, (less than l'' different from the preceding): and con- 

 versely, for a duration of 4 days 15 hours a daily temperature of 83,5° Fahr, 

 is required in Georgia, and 76,85° Fahr, in Ohio. That is to say, a certain rise 

 in temperature may have more effect in a colder climate than in a hotter one: 

 and at the same temperature a certain stage of a species may last for different 

 periods in countries whose general climatic conditions are different. Sections 2, 

 3, 4 and the accompanying tables deal with duration of postembryonic and adult 

 stadia, and with effects of starvation on duration of life. In a few observed cases, 

 poor nourisliment during the immature stages seemed to have little or no effect 

 on the duration of adult life. H. Scott (Cambridge). 



891) Morley, C, The cause of humming in the air. In: Ent. Mo. Mag., 

 Bd. XXIII, Heft 11, S. 259—262, 1912. 



In hot summer-weather a humming sound is frequently heard in the air in 

 quite open places, though no insects which might produce it are visible. Among 

 trees it might be caused by bees, but in open places this is unlikely, since bees 

 have not the habit of congregating in large numbers at such a height as to be 

 invisible. In the evening of July 12"^ the writer found that this sound was caused 

 by large numbers of 2 species of Chironomidae {Tanypus varius Fabr. and C/iiro- 

 nomus dorsalis Meig.): their presence was revealed by the fact that when Struck 

 by gusts of wind they descended low enough to be seen, but in the lulls between 

 the gusts they ascended so high as to be invisible though distinctly audible. 



H. Scott (Cambridge). 



892) Neave, S. A., Notes on the blood-sucking insects of Eastern Tro- 

 pical Africa. In: Bull. Ent. Research, Bd. III, Heft 3. S. 275— 323, Taf.X,XI, 

 1912. 



This report deals with the blood-sucking insects coUected by the writer in 

 his journeys (as travelling Entomologist to the Ent. Research Committee, London) 

 in 1910 — 1911. The countries travelled over were Nyasaland, British East Africa 

 and Uganda, with parts of N. Rhodesia and German East Africa. The area 

 visited comprises a large part of the Eastern Tropical subregion, a small part 

 of the South African subregion, and of the Western tropical subregion: it con- 

 tains every type of country and elevations from sea-level to 10000 feet. Out of 

 a collection of all forms of insects of about 100000 specimens, about 15000 were 

 blood-sucking arthropods. The blood-sucking insects are treated in systematic 

 Order, with notes on distribution, bionomics, etc. 



Some general account is given on pp. 279 — 282 of the Tabanidae, which 

 comprise the greatest number of African blood-sucking flies. These flies are most 

 numerous, especially the c?, immediately before and after the commencement of 

 the rains: for there is evidence that they emerge from the pupae before the 

 rains commence. They are peculiarly sensitive to climatic conditions, different 

 genera requiring different amounts of sunshine, humidity etc. Where there is 

 only one wet and one dry season, conditions are fairly simple: but in East Africa, 

 where there are two well-marked rainy seasons, most species have probably at 

 least two broods in the year, and in the low-lying parts of the country few if 

 any can be found in the hottest and driest months. Again in Uganda, where 

 wet and dry seasons are ill-defined and more or less humidity is always present, 

 many species appear to be on the wing throughout the year: this is also the 

 case in cool and moist mountain-forests at high elevations in other districts. In 



