325 



bees remain healthy and free from Nosetna for a considerable time and 

 survive the following winter, as there is no difficulty in stimulating 

 affected bees in such a way that they temporarily throw off all the 

 symptoms usually associated with this disease. 



Jack (R. W.). The Turnip Sawfly {Athalia fkicca, Konow.)— 

 Rhodesia Agric. Jl., Salisburij,xiv, no. 2, April 1917, pp. 206-212, 

 2 plates. 



Athalia flacca, Kon., formerly erroneously recorded as A. rosae, L. 

 [see this Review, Ser. A, ii, p. 236], attacks all cultivated Cruciferae 

 throughout Rhodesia, its native food-plants being unknown ; in 

 severe infestations the crop may be entirely stripped of its leaves. 

 The eggs are laid in slits made in the edges of the leaves, where the 

 newly hatched larvae begin to feed. After about 17 days, the larva 

 descends about one inch into the soil where it constructs a tough 

 cocoon, the pupal stage lasting at least 10 days. There are apparently 

 at least four complete broods during the year ; these overlap, the 

 greatest injury being done by the larvae present in January and 

 February. Contrary to the habits of moths with a similar life-history, 

 such as Laphi/gma exigua, Hb. (pigweed caterpillar), Hellula undalis, 

 F. (cabbage web worm) and PluteUa jnaculipennis, Curt., the adult 

 sawflies that emerge during the dry season have never been recorded 

 as injuring crops grown under irrigation ; in fact dry weather is 

 apparently inimical to the increase of this sawfly. As the insect 

 becomes less abundant towards the close of the rainy season in s]>ite of 

 continued abundance of food, it is probably checked to some extent by 

 natural enemies, though only one parasite, a Tachinid fly, has as yet been 

 bred from specimens collected in the field. Experiments with arsenate 

 of lead sprays against the mature larvae, which have been tried for 

 several years, have led to the conclusion that in order to kill the grubs 

 arsenicals must be used in such strength that they would injure the 

 plants. Adult sawflies can be controlled by a weekly spray of 1 lb. 

 lead arsenate to 16 gals, water ; the best control for the larvae on 

 young crops is a spray of paraffin emulsion, made of 1 lb. soap dis- 

 solved in 2 gals, water to which 4 gals, paraffin oil are added to make 

 a concentrated emulsion ; this should be used in the proportion of 

 one part to nine parts water. The spray must be applied with force 

 and causes many grubs to fall from the plants, so that the ground 

 beneath must also be well sprayed. 



Pead (C. H.). Cicadas and their Relatives. — Rhodesia Agric. Jl., 

 Salisbury, xiv, no, 2, April 1917, pp. 240-247, 3 plates. 



This paper describes the chief characteristics of the Cicadidae and 

 the allied families w^th notes on their life-histories. These Homop- 

 tera probably destroy about one-sixth of the total crops in Rhodesia 

 and the only remedy that can be suggested against their depredations 

 is cultivation, as they are less abundant on well cultivated ground. 



MozNETTE (G. F.). Three Insects affecting Clover Seed Production. — 

 Oregon Agric. Coll. Extn., Corvallis, Bull. no. 203, April 1917, 

 4 pp., 5 figs. 



The injury to clover in Oregon by Perrisia leguminicola (clover-seed 

 midge) and Bruchophagus funebris (clover-seed Chalcid) has already 



