280 



There was great mortality of hibernated larvae of K. rohustus owing 

 to a fungus which attacked them even in dry conditions. The hyphae 

 radiated out from the attacked larvae, and any others close by soon 

 became infected. The author was able to feed larvae of Coccinella 

 bipuncfafa in captivity on larvae of the pea thrips, but in the wild state 

 he never found these larvae m the infested flowers, and believes that 

 they exert little, if any, controlling influence. Vuillet [see this Revvjiv, 

 Ser. A, ii, p. 488] has recently described Thripoctefins brui as parasitic 

 on K. rohustus from France, but this Chalcid has not been found in 

 England. 



Wet weather always causes great mortality among thrips and also 

 causes the plants to grow more rapidly, but in this species rain has 

 less effect, owing to the sheltered position of the msects in the flowers. 

 The pea thrips is most prevalent on light or gravelly soils, and it is 

 probable that the conditions in a light soil are more suitable for the 

 hibernating larvae. No variety of pea or bean is immime to the 

 attacks of K. rohustus, but the earlier so^\^l plants usually escape severe 

 damage. 



Artificial control of this insect is difficult. Spraying is only of use 

 when the larvae are feeding openly on large pods. Any contact spray 

 (soft soap, resin, etc.) should give good results and on a small scale 

 the following stock solution has been found to be successful : water, 

 1 qrt. ; soft soap, 3 oz. ; and tobacco powder, 3 oz. ; the whole to 

 be boiled for a short time and diluted for use in about one part to 

 twenty of water. Soil fumigation during the winter should give good 

 results, but must be done to a sufficient depth. Rotation of crops 

 should be practised wherever possible, and peas and beans gro^vii as 

 far as possible from the areas attacked in the previous year. The 

 aldehydes recommended by Hewlett [see this Review, Ser. A. ii, p. 271 ] 

 were tried, but were not found to attract this species. The burning 

 of the pea sticks during the winter, which is frequently recommended, 

 is useless. A few notes on the collecting and breeding of thrips are 

 given. A bibliography of 30 references is appended to this article. 



AwATi (P. R.). The Apple Sucker, with Notes on the Pear Sucker. — 



Ann. App. Biol., London, i, nos. 3 & 4, January 1915, 

 pp. 247-272, 2 pis., 21 figs. 



This study of Psylla mali (apple-sucker) was made at Brentford, 

 Middlesex, during the summer of 1913, but as the life-history of 

 this insect occupies a whole year, no stage repeats itself in one season, 

 and the author was unable to repeat or check his observations. 



The eggs are laid singly on the twigs of the apple tree and are 

 distributed irregularly, the new twigs of the first year's growth being 

 chosen by the female. The eggs are found along the scars on the 

 twigs left by the leaf petioles. The egg is described in detail. The 

 larvae generally begin to hatch in the last week of March and may 

 contmue to do so until the end of April. The larva crawls towards 

 the apical bud of the twig, and if the bud is not yet opened, it can 

 live without food for two or three days. There are, in all, five instars, 

 the last of which is here called the nymph. Each instar is described 

 and figured and the period occupied by each stage tabulated, A 

 detailed account of the habits of the immature stages is given and 



