135 



erratic responses. A degree of warmth somewhat above that of the 

 surrounding air was highly and consistently attractive to a certain 

 percentage of the mosquitos. A joint of stove pipe placed in the woods 

 and heated by an alcohol lamp attracted about as many mosquitos 

 as were attracted bv persons in the vicinity. 



In laboratory experiments with Culex pipiens, heat was similarly 

 attractive the maximum response occurring at temperatures between 

 90° and 110° F., these being from 15° to 30° higher than the surrounding 

 air. Temperatures about 120° and below 85° proved less attractive, and 

 at 140° the mosquitos were entirely dispersed. The response was 

 decidedly increased when the breath was passed through the warm 

 water, used to create the high temperature, in place of the usual air 

 current, but the admixture of various amounts of carbon dioxide with 

 the air stream did not increase the attraction compared with that 

 shown for undiluted air. 



Several types of heat traps were tried in the field, even the crudest of 

 which proved attractive, though the mosquitos were able to escape 

 from all of them. In cages they feed readily on a solution of potassium 

 arsenite in sweetened water ; this substance being highly toxic, it is 

 suggested that it might be used as a poison bait in heat traps. Traps 

 have also been devised in which the mosquitos are destroyed upon 

 entering a chamber containing potassium cyanide, but these have not 

 yet been tested in the field. 



RouBAUD (E.). Sommeil d'Hiver cedant a I'Hiver chez les Larves et 

 Nymphes de Muscides.— C.i?. Hchdom. Acad. Sci., Paris, clxxiv, 

 no. 14, 3rd April 1922, pp. 964-966. 

 The phenomenon of hibernation in various Muscids is discussed. 

 They may apparently be divided into two groups : (1) flies such as 

 Stomoxvs calcitrans, the house-fly [Miisca domestica], Drosophila spp., 

 etc., in'which the advent of cold induces a suspension of activities, but 

 in which, as soon as the temperature becomes more favourable, develop- 

 ment continues uninterruptedly; and (2) flies, such as Lncilia, etc., 

 in which a period of inertia is essential for development. Certain 

 pupae belonging to the latter group will not produce adults if they are 

 not subjected sufficiently to cold. 



Phibbs (G.). The Larval Mouth-hooks of Hypoderma.— Irish 

 Naturalist, Dublin, xxxi, no. 3, Maich 1922, pp. 25-30, 6 figs. 



Attention is drawn to Laake's mistake in supposing that the second- 

 stage larva of Hypoderma had not been recognised before [R.A.E., 

 B, ix, 171] ; it was briefly described and figured by Carpenter and 

 Prendergast in Journal Dept. Agric. S- Tech. Instr., Ireland, ix, no. 3, 

 1909. 



The occurrence of mouth-hooks in the first-stage larva of Hypoderma 

 bovis, DeG., and H. lineatum, Vill., is discussed. From an examination 

 of H. bovis taken from the gullets of cattle in Ireland, this character 

 was found to be equaUy evident in the second stage. 



Herzog (M. a.). Zur Biologie der Dasselfliege. [A Contribution to 

 the Biology of the Bot ¥W."i—Riv. Biologia, Rome, iii, no. 4, 

 November-December 1921,^ pp. 747-780, iv, no. 1, January- 

 February 1922, pp. 23-43. 

 This title covers two papers, of which only the first deals with modern 

 advances in the knowledge of the biology of Hypoderma bovis, DeG., 

 and H. lineatum, Vill., and in methods for combating them, while 



(6838) M 2 



