27 



NOTES ON AFRICAN COTTON INSECTS. 

 By Fred. V. Theobald, M.A. 



In these days of development of cotton cultivation in Africa 

 much interest has been centred on the work of cotton insects. 

 It has been justly thought that, with the importation of seed 

 from one part of Africa to another, and from America and the 

 West Indies, &c., to Africa, we should be introducing numbers 

 of strange cotton insects. 



Undoubtedly the worst cotton pests in America and the West 

 Indies are the cotton boll weevil {Anthonomus grandis, Boh.), 

 the cotton boll worm {Heliothis obsoleta, Fabricius), and the 

 cotton worm \Aletia arfjillacea, Hubner).t 



In recently going over the cotton pests of the world, I have 

 come to the conclusion that very few insects are likely to be im- 

 ported in seed to Africa ; the most important are the cotton boll 

 weevil, and a small Tineid moth (Srewte^?s?/M?i?fsn<7a,Walsingham), 

 the larvae of which have been noticed boring into cotton -seed in the 

 West Indies. A sharp look-out should undoubtedly be kept for 

 both pests amongst the seed, especially for the weevil, for it may 

 sometimes be found hybernating amongst the seed in numbers. 



Before very long we are sure to hear of the cotton boll worm 

 of America (Heliothis obsoleta) attacking cotton in West and 

 Central Africa. The conclusion might possibly be formed that 

 it bad been imported. 



This widely distributed moth is known in Africa already as 

 a true native species. It has been found in the Sudan, in 

 Abyssinia, in British East Africa, in North Gamiland ; it occurs 

 all over Cape Colony, the Orange River Colony, the Transvaal, 

 in Natal and Basutoland. It attacks mealies and other native 

 corns. I rather fancy from the description sent me that it has 

 already started attacking cotton in Mozambique. 



At present all the cotton pests known in Africa are confined 

 as cotton pests to that continent, except the omnivorous cutworm 

 {Afjrotis ypsiloii, Rott.), known in America as the greasy cutworm. 



The best known are those found in Egypt, namely, the cotton 

 boll worm {Earias insulana, Boisduval), which also occurs in 

 Sokotra at 3500 feet. 



The Egyptian cotton worm [Prodenia littoralis, Boisduval), 

 which attacks the leaves, and concerning which the Khedivial 

 Government has recently issued instructions to be enforced for 

 its eradication. 



The small cotton worm (Caradrina exigua) recently worked 



* Read before the Association of Economic Biologists, at Liverpool 

 Dec. 29th, 1905. 



f The cotton boll worm of America has alwaj's been known as Heliothis 

 armiger, Hiibner (1796), but it is now known to be the Bomhyx obsoleta of 

 Fabricius (Ent. Syst. 3, i. p. 456, 1793). ^ .2 



