453 



delicate plants and 4 or 5 lb. in the same quantity of water for hardy 

 plants. Arsenite of soda has the advantages of being cheap and of 

 remaining in suspension for a long period. The formula for a stock 

 solution is 1 lb. white arsenic, 2 lb. washing soda, 2 gals, w-ater. The 

 stock solution is made up to 50 gals, before use, and for dehcate plants 

 from 2 to 3 lb. slaked lime are added. Calcium arsenite spray is 

 prepared according to the formula, 1 lb. white arsenic, 2 lb. stone lime, 

 and 2 gals, water ; a quart of the stock solution is diluted to 75 gals. 

 for use on dehcate fohage. 



Formulae are given for the preparation of poisoned baits, lime- 

 sulphur wash and other contact sprays. For destroying or acting as a 

 deterrent against underground insects, tobacco dust is recommended. 

 The surface soil is removed from around the base of the plant, tobacco 

 dust is scattered in the depression and water sprayed over it. Soft- 

 bodied insects have been successfully controlled by a contact spray 

 consisting of 1 lb. hard soap, 1 pt. crude carbohc acid, and 

 30 gals, water. A preparation consisting of 2 gals, whale oil soap, 

 3 gals, red engine oil (25° Be.), and 1 gal. water, diluted with 

 50 gals, water before use, is recommended for treatment of Aphids, 

 red spider, and cabbage caterpillars. A long Hst of garden vegetables 

 with the common and scientific names of their insect pests is appended 

 to this paper. 



Mason (C). Report of the Government Entomologist. — Ann. Rept. 

 Dept. Agric. Nyasaland for the Year ended 31st March 1916, 

 Zomba, 30th June 1916, pp. 19-22. [Received 4th September 

 1916.] 



Cotton was generally attacked by boll-worms and leaf-hoppers. 

 A flea-beetle caused severe damage in one district and the stem-boring 

 larva of a Cerambycid in another. Pests of tobacco were the same as 

 those in previous years ; Phthorimaea was abundant, Chloridea and 

 Prodenia occurred on young plants, while shipments of tobacco were 

 damaged by Lasioderma. Maize was injured to a certain extent by 

 Prodenia, Phytometra (Plusia) clialcites, Esp., and Cirphis loreyi, Dup. 

 The absence of the.borer, Busseola fusca, Hmp., was marked. Eight 

 species of Saturniidae were reared, but none gave silk of a com- 

 mercial value. Anaphe anibrizia, Butl., was taken at night from 

 December to March. A. panda, Boisd., was abundant at Zomba on 

 Bridelia micrantha and is under investigation. The larvae were heavily 

 parasitised by two or possibly three species of Tachinids. Teflt grass 

 was severely injured during April by the larvae of the Noctuid, 

 Laphygnia exempta, Wlk. This species was parasitised by the Bomby- 

 Hid, Villa flavescens, Bez., the Ichneumon, Paniscus testacens, Grav., 

 var.o^acMZMS,Thoms.,and to a lesser degree by another Ichneumon and 

 a Chalcid. The migration of a swarm of caterpillars belonging to 

 15 dijSerent species from an area of cleared bush to tobacco, maize, etc. 

 was observed in one district. The migration was due to the destruction 

 of the native food-plants. 



Several species of fruit-fUes were recorded during the year. Ceratitis 

 rosae, Karsch (mango fruit-fly) required about 24 days to complete 

 the larval, and from 9 to 1 1 days to complete the pupal stage. Ceratitis 

 sp, was reared from peach and guavas. Dacus bivittatus, Big. (pumpkin 



