550 



obvious that in regions infested with P. chrysocephala winter sowings 

 should be delayed, or that Brassica napits be replaced by winter 

 B. rapa. This retarded sowing applicable to Psylliodes will also serve 

 against Phyllotreta spp. It was also noticed that an August field 

 attracted all the Psylliodes in the neighbourhood, so that a September 

 field remained untouched. Trap-crops could perhaps be grown with 

 advantage ; they should be in full growth in August, and may be 

 ploughed under from mid-October onwards. 



The last section of this paper deals with the application of statistical 

 methods to cotton pests in East Africa in 1914-15. The net-catches 

 were astonishingly varied, according to the maturity of the plants 

 and the character of the soil. Proof was obtained that the Jassid, 

 Chlorita facialis, is connected with crinkling disease. In one instance 

 100 sweeps of the net yielded 18 individuals in a healthy field and 720 

 in one near by infected with the disease. 



Clausen (P.). Entwicklungsgeschichtliche Untersuchungen iiber den 

 Erreger der als "Kalkbrut" bezeichneten Krankheit der Bienen. 



[Investigations on the Life-history of the Causal Agent of the 

 Bee Disease known as " Limebrood."] — Arb. Biol. Reichsanst. 

 Land- u. Forstw., Berlin, x, no. 6, 1921, pp. 467-521, 24 figs., 

 3 plates. 



The development of the fungus, Pericytis apis, causing " limebrood " 

 in bees, is described. 



BoRCHERT (A.). Die Formaldehyddesinfektion in der Bienenwirtschaft 

 in der Form des Autanverfahrens sowie experimentelle Unter- 

 suchungen iiber die Tiefenwirkung des mit Wasserdampf gesattigten 

 Formaldehydgases. [The Autan Method of Formaldehyde Dis- 

 infection in Apiculture and Experiments on the Penetrative 

 Power of Formaldehyde Gas saturated with Steam.] — Arb. Biol. 

 Reichsanst. Land- u. Forstw., Berlin, x, no. 6, 1921, pp. 522-557. 



For combating bee diseases, especially foulbrood, Maassen introduced 

 an efficient method of disinfecting the combs by melting them down in 

 a steam melter. Many apiarists have believed that formaldehyde 

 gas is also effective for this purpose, but the investigations here 

 described show that it is quite unsuitable. 



Gardner (J. C. M.). The Celery Fly ; Life-history, Damage to Plants, 



and Control. — Friiit-grower, Fruiterer, Florist and Mkt. Gdnr., 

 London, li, nos. 1,328-1,330, 12th, 19th and 26th May 1921, 

 pp. 829-831, 863-865 and 896-897, 7 figs. [Received 26th 

 September 1921.] 



The systematic position and synonymy of Acidia heraclei, L. (celery 

 fly) are discussed, and its distribution is reviewed. Its food-plants 

 belong to the Umbelliferae and Compositae. The author has reared 

 the species from larvae taken on celery {Apiiirn graveolens), parsnip 

 {Pastinaca sativa), cow parsnip {Heraclenm sphondylium) , H. giganteum 

 and chervil {Chaerophyllum cerefolium). A description is given of the 

 various stages. In captivity the adult flies live for about seven weeks, 

 but under natural conditions their life is probably very much shorter. 

 The process of oviposition is described [R.A.E., A, vi, 480]. The 

 eggs hatch in 6 to 14 days, according to the temperature; the larval 



