22 



Graham-Smith (G. S.)- Further Observations on the Habits and 

 Parasites of Common Flies. — Parasitology, Cambridge, xi, no. 3-4, 

 October 1919, pp. 347-384, 2 charts, 2 plates, 23 figs. 



The habit of cleansing themselves exhibited by flies and the influence 

 of weather upon them is discussed. With regard to the latter, 

 experiments show that the curve indicating the number of flies caught 

 corresponds with that for the maximum temperatures recorded by 

 a thermometer exposed in the sun. The flies caught during these 

 experiments in 1914, 1915 and 1916 included Morellia hortorum, 

 Graphomyia maculata, Polietes alholineata, Pyrellia eriophthalma and 

 Phormia azurea (groenlandica). These species were less common 

 in 1915 than in the other years. Many species were examined for 

 the presence of the fungus, Empusa, which was found to attack 

 Calliphora erythrocephala, Lucilia caesar, Hydrotaea dentipes, Fannia 

 canicularis, Anihomyia radicum, Sarcophaga carnaria, Musca corvina 

 and Scatophaga stercoraria. 



The natural enemies of flies include mites, the beetles, Creophilus 

 maxillosus, Necrophorus humator, Hister cadaverinus and Pterosticlms 

 madidus, as well as numerous parasites. 



The latter, which are discussed and illustrated, include Cynipids, 

 DirancJiis sp., Kleidotoma sp. and Figites sp., all of which emerged 

 from the puparia, in which they had hibernated : Proctotrupids, 

 Trichorpia sp, ; T. ? elongata, Thoms, ; several species of Aneurrhynchus ; 

 and one individual of a species of Conostigmus or Lygocerns : 

 Ichneumonids, Phygadeuon specidator. Thorns., and Atracfodes bicolor, 

 Gravenh., obtained from puparia of C. erythrocephala : Chalcids, 

 Melittobia acasta, Wlk., which often attacks puparia previously 

 infested by Alysia manducator ; Dihrachys cavus which oviposits in 

 normal puparia of M. stabulans and P. azurea (groenlandica) as well 

 as in puparia already parasitised by Alysia manducator ; Nasonia 

 brevicornis ; Muscidifurax raptor ; Necremnus leucarthros, Thoms. ; 

 Spalangia hirta, Hal. ; and Stenomalus muscarum, of which the last- 

 named although found hibernating in company with flies has not 

 been obtained from fly puparia : Braconids, Alysia manducator ; 

 Aphaereta cephalotes, Hal. ; Aspilota fuscicornis, Hal. ; and A. nervosa , 

 Hal. 



Bacot (A.) & LiNZELL (L.). The Incubation Period of the Eggs of 



Haemato'piniis asini. — Parasitology, Cambridge, xi, no. 3-4, October 

 1919, pp. 388-392. 



Of the three species of lice, Trichodectes equi, T. pilosus and 

 Haematopinus asini, found on horses the last is the most important, 

 as it occurs most frequently, causes greatest irritation, and apart from 

 the general symptoms caused by its presence, is most difficult to 

 eradicate, for apparently clean horses may become reinfested after 

 the lapse of a few weeks. Investigations here described show that 

 the normal incubation period is from 16 to 20 days, with a minimum 

 under natural conditions of about 15 to 16 days. Moist cold kills 

 the eggs, but dry cold only killed 50 per cent, at a temperature of 

 50° F. for a week and increased the incubation period of the remainder 

 to 18 days. Dry heat very quickly kills the eggs. To prevent 

 possible re-infestation by lice emerging from eggs with an abnormally 



