202 TPIE SCOTTISTT NATURALIST 



D. depressJis, but they may be separated by the difference in the 

 shape of the thorax in both sexes, by the different curvature of the 

 anterior tarsal claws of the male, and by the difference in the 

 breadth of the apex of the pedeagus. The distribution of both 

 species in Britain is discussed in considerable detail. 



The "Egg-Burster." In the Annals and Magazine of Natural 

 History for April (pp. 372-376) F. W. Edwards draws attention to 

 the presence in the larvae of several diptera, belonging to different 

 famihes, of a curious organ knowMi as the "egg-burster." It consists 

 in general of a chitinous disc armed with a small pointed peg, 

 situated on the head of the larva but only present in the first stage, 

 i.e., before the first moult takes place. This apparatus, whose 

 function is to pierce and cut the egg-envelope and thus facilitate the 

 exit of the grub, has only hitherto been observed among diptera in 

 the family Culicida^ (Gnats), but Mr Edwards has discovered it 

 also in Siniitlii/nt, Chironomi/s. and two genera of Mycetophilidffi 

 (Fungus-gnats). In other orders of insects the egg-burster has long 

 been known, assuming a variety of forms. 



Frit-fly {Oscinis frit) in Scotland. In the July number of 

 the Scottish Journal of Agriculture., Dr James Ritchie gives illustra- 

 tions of the amount of damage to oats caused by the Frit-fly in the 

 south of Scotland, and summarises recent investigations bearing 

 upon methods of combating this pest. 



Horse Bot-flies in Britain. In view of the increase of Bot- 

 flies due to the unusual bunching of horses in paddocks and fields 

 during the war, and because of the possible spread of Bot-flies and 

 bot-diseases in Britain through the dispersal of infected horses, Dr 

 James Ritchie gives a short illustrated summary of habits of the 

 flies, of their effects upon horses, and of measures which have been 

 recently adopted with effect in preventing and curing bot-disease 

 {Scot. Jour n. Agr., 1919, p. 354). 



Diptera at Aberfovle. In a note in the Entomologisfs 

 Monthly Magazine for October 1919 (p. 233), A. E. J. Carter 

 records the capture of the following Diptera during the past summer : 

 Oxycera dives., Liv., and Physocephala nigra, Deg., at Aberfoyle ; 

 Sytnphoromyia crassicornis, Pz., at Balquhidder ; Therioplectes micans, 

 Mg., T. distinguerdus, Verr., Hcetnatopota crassicornis, Whlbg., and 

 Chrysops relicta, INIg., at Loch Voil (the last-named also at Loch 

 Lubnaig) : Isopogon brevirostris, Mg., Polietes hirticrura, Mde (both 

 sexes), and Hydrotcea pilipes, Stein, at Callander. 



