32 



to cover the hair after treatment. The odour of paraffin can be con- 

 cealed by the addition of a smah quantity of an essential oil or other 

 scent, such as oil of mirbane (nitro-benzol) or camphor. The latter 

 has the advantage of allaying skin irritation. 



Grassi (B.). Nuovo Orizzonte nella Lotta antimalarica. (Memoria 

 preliminare.) [A New Horizon in Anti-malarial Work. (Pre- 

 liminary Memoir.)] — Riv. Biologia, Rome, iii, no. 4, July-August 

 1921, pp. 421-463. 



In the marshy market-gardens at Schito, on the Bay of Naples, there 

 is a biological race of Anopheles maculipennis [claviger) that lives 

 exclusively on domestic animals. It is only in closed spaces and when 

 driven by hunger that it can be induced to attack man. This dislike 

 for man seems to be to some extent hereditary and to date from a 

 period between 1860 and 1885, when the locality contained a herd of 

 cattle, tended at night by only a few men. The mosquitos thus 

 became accustomed to attack domestic animals only. As a result, 

 malaria has disappeared from Schito, though A. maculipennis 

 abounds. 



At Massarosa, a similar state of things must have occurred at some 

 period, for malaria disappeared there also. Owing, however, to the 

 relative scarcity of cattle and the abundance of A. maculipennis, due 

 to the presence of rice-fields and marshes, a man-attacking race of the 

 mosquito is gradually reappearing, and a slight recrudescence of malaria 

 has been observed in recent years. 



It is therefore legitimate to try to combat malaria by using the 

 protection afforded by cattle, but whether this is feasible on a large 

 scale remains to be seen. In tropical countries where cattle are scarce 

 or absent, Anophelines mainly attack man, and this is certainly one 

 of the factors that aggravate the malarial conditions there. 



In view of this preference for domestic animals, the measures directed 

 against adult mosquitos may defeat their object, the greater ease with 

 which captures are effected in pigsties and cowsheds as compared with 

 dwellings resulting in a tendency to eliminate the individuals that 

 prefer animals to man. Screening, which has not been much favoured 

 in Italy, thus acquires a great importance, as it tends to encourage 

 the habit of avoiding man. 



The fact that A. maculipennis occurs in varying and sometimes 

 enormous numbers in districts where malaria has disappeared, and that 

 in some of these places it seldom or never bites, must be an incentive 

 to find a method for rendering it innocuous. The fact that cultivation 

 of an intensive character drives away malaria is explained by the 

 correlated increase in domestic animals. Such animals are not onty 

 numerous, but they are usually kept in shelters that are more or less 

 dark, dirty and warm, and therefore attractive to Anophelines. The 

 latter are thus brought to attack animals by preference, and gradually 

 cease to bite man. 



Hirst (S.). Notes on Parasitic Acari. A. On the Presence of a System 

 of Tracheal Tubes in the Families Sarcoptidae and Listrophoridae. 

 B. Note on the two Valid Species of the Genus Psoroptes {P. 

 natalensis and P. communis). — Jl. Quekett Micros. Club, London, 

 Ser. 2, xiv, no. 87, November 1921, pp. 229-236, 3 figs. 



The contents of this paper are indicated by its title. 



