AND PROBLEMS OF SOUTHERN NIGERIA. 205 



a year old and had been grown from seed planted at stake. It was densely 

 shaded with pigeon pea. The cocoa at Ibadan varied in age from 2 to 7 months 

 and grew under palm-leaf shades in baskets containing about 20 plants or in 

 nursery beds. There were a few plants over a year old. The varieties included 

 Red and Yellow Pod from the Agege district, Yellow Pod from the Gold Coast, 

 and Amelonado. 



There was very little opportunity for a study of the insects affecting bearing 

 plants, but the cocoa farms of the Agege district were visited several times and 

 the farms around Aba (Eastern Province) were visited while on tour. 



Harmful Insects. 

 Leaf-eating caterpillars. 



Diacrisia maculosa, Stoll (Plate XXV, fig. 4). 



This moth was found to be very plentiful at Agege and Ibadan, and it is 

 widely distributed throughout Africa. The caterpillars are voracious feeders, 

 being found on cocoa, kola, cotton and maize. They were found on maize at 

 Ibadan in October 1911 ; they were very common, late in June 1912 and 

 onwards, on maize and cocoa growing near each other at Agege ; early in July, 

 at Ibadan, they were abundant on cocoa and maize, and from August onwards, 

 on young cotton. They are very active in habit, crawling quite long distances 

 in search of food, and have been frequently observed crossing from cocoa beds 

 to maize. 



The moths may be found in the early morning resting motionless on different 

 parts of the plants and may then be easily caught. 



The contrast between the appearance of the caterpillar before and after 

 moulting is very striking. Before moulting the caterpillar loses its dark hair 

 and the body appears banded alternately with vivid yellow and dark brown. 

 After moulting the long dark hairs conceal the strong coloration. 



The cocoons are about an inch in length and are made of the dark hairs of the 

 caterpillar meshed together with silk. They have not been found in the field. 

 The pupal period is from 13-18 days. 



A Tachinid fly (Sisyropa) is known to be a natural check. 



Prodenia litura, F. (Plate XXIV, fig. 9). 



The caterpillars have been found quite commonly at Agege and Ibadan, and 

 especially so among nursery cocoa at Calabar. The insect is widely distributed 

 throughout the Tropics, and is likely to be found all over Southern Nigeria. 

 The larvae prefer the leaves of cocoa to those of cotton and okra, but will 

 flourish on any of them. They are common from May to November, but no 

 special broods were noticed. 



Mctopius discolor, Tosq., an Ichneumonid, has been bred from a larva of this 

 species. 



Diacrisia sp. 



This moth was only met with at Ibadan, where the caterpillar is quite common. 

 It is densely covered with brush-like tufts of mouse-grey hair, and attains about 

 1 inch in length. It is very active and, like that of D. maculosa, may be seen 

 travelling across open ground. It feeds on cocoa and cotton leaves. 



