4:68 SUMMARY OF CURRENT KESEA.RCHES RELATING TO 



reckoned in millions of pounds sterling. There is great need for a 

 comprehensive work on British Diptera, which number considerably 

 over 300(1. It is interesting that out of the seventy-four existing 

 families of Diptera no fewer than sixty-four are represented in the 

 British Fauna. 



Diptera Scotica.* — Percy H. Grrimshaw continues his survey of 

 the Diptera of Scotland, and deals in this instalment with those from 

 the Western Isles. The list includes 380 species. Jura heads the list 

 with 166 ; then follow Lewis with 150, South Uist with 14:8, North 

 Uist with 90, and Skye with 78. Of the smaller islands we have 

 Benbecula with 27 species, and lona with 22. But no deductions can 

 be drawn until the islands are thoroughly and systematically searched 

 on a uniform plan. 



As regards Lice.f — J. Parlane Kinloch has continued his investiga- 

 tion of the best methods of destroying lice. As Bacot has also shown, 

 they do not survive immersion in boiling water. Naphthalene and 

 creosote (as in N.C.I, powder) have a strong insecticidal action. The 

 lethal power of naphthalene is greater in the commercial form than in 

 pure naphthalene, and seems to depend in great part on the presence of 

 hydrocarbons and coal-tar derivatives other than pure naphthalene. 

 The iodoform which is mixed with naphthalene and creosote in N.C.I, 

 powder has a feeble insecticidal action, but increases the adhesiveness of 

 the powder to cloth. The cheaper magnesium silicate might be sub- 

 stituted for it. The insecticidal power of naphthalene-creosote powders 

 gradually diminishes when they are exposed in the open air. All lice 

 exposed to an atmosphere of sulphur dioxide die within five seconds. 

 For emergency cleansing of clothing immersion in petrol is most suitable, 

 for the scalp tetrachlorethane on cotton-wool. 



Malaria Parasites in American Species of Anopheles. | — W. V. 

 King finds that Anopheles jmndifennis is an efficient host of the 

 organisms of tertian and jestivo-autumnal malaria, and A. crucians of at 

 least aistivo-autumnal malaria. Information has been obtained as to the 

 relative susceptibility of these two species and of A. qicadrimacvJatus, 

 which has been known as an efficient host since Thayer's experiments 

 in 1900. The indications are that A. punctipennis and A. quaclrima- 

 culatus are equally susceptible to infection with Plasmodium vivax ; 

 while with P. falciparum, A. crucians showed the highest percentage of 

 infection (75 p.c), A. p)unctipennis second (33 p.c), and A. quaclrima- 

 culatus third (23 p.c). 



Beet or Mangold-fly.§ — A. D. Imms discusses the distribution 

 and life-history of Pegomyia hyoscyami var. hetae, which attacks beet, 



* Scottish Nat., 1914, pp. 205-13, 234-6, 258-62, 276-81 ; 1915, pp. 115-19 ; 

 1916, pp. 134-8. 



t British Med. Journ., June, 1916, pp. 1-11. 



t Journ. Exper. Med., xxiii. (1916) pp. 708-16 (8 pis.). 



§ Journ. Board Agric, xxii. No. 9 (December, 1915) 3 pp. 



