192 A. t>. PEACOCK — ENTOMOLOGICAL PESTS 



INSECTS AFFECTING COTTON. 



Most of the research on the insects of cotton was prosecuted at the headquarters 

 of the Agricultural Department, Ibadan, during the latter part of the 1911 cotton 

 season and the early part of the 1912 season ; during 1911 attention was princi- 

 pally directed to the Red Cotton Stainer. In that year, the Department had 

 about 90 acres of cotton under experiment, mostly in 10-acre blocks, and, in 1912, 

 about 50 acres in 5-acre blocks. Nyasaland, Meko and Ishan cottons were 

 cultivated, but the bulk was American of the varieties Georgia, Truitt's Big 

 Boll, Mebane and Upland. Agege cotton was grown from seed which the native 

 farmers at Agege had mixed, the mixture being of native and American seeds. 



The entomological work was done in conjunction with the efforts of the 

 Agricultural Department to find the most suitable variety of cotton for Southern 

 Nigeria. Consequently the Nigerian pests on American cotton were principally 

 studied. Reference to work on native cottons is frequently made. The accounts 

 of many of the insects must be regarded as preliminary, particularly those parts 

 dealing with Parasitic Hymenoptera, Aphidae and Coccidae. 



Harmful Insects. 

 Cotton Stainers. 



Dysdercus super stitiosus, F. (Plate XXIII). 



The Red Cotton Stainer Bug has been observed at Ibadan and Agege in the 

 Western Province, at Benin City and Ugboha in the Central Province, and at 

 Calabar in the Eastern Province. From these observations and the amount of 

 stained cotton brought into the markets from the surrounding outlying districts 

 it may be concluded that the bug is widely distributed throughout the Colony. 



The adults and young have very similar habits. They are mostly in evidence 

 during March, the time of ripening and shedding of the seed of the silk-cotton 

 tree, and from September to the end of November during the ripening of the 

 cotton bolls. They creep over the ground, sheltering under the low bush plants 

 and weeds which have survived the clearing of the cotton field, and climb actively 

 over the leaves, flowers and bolls of the cotton plants. They show a distinct 

 preference for shade during the heat of the day. As the cotton season advances 

 they simply swarm (Plate XXIII, fig. 10). 



These insects suck the juices of the rich oily seeds of the cotton and silk-cotton 

 tree, and stain the white lint or down of their food-plant with yellow excretory 

 juices. At Ugboha, during April 1912, a somewhat striking observation was 

 made ; a number of young stainers, about three weeks old, were found sucking a 

 dead snail. Instances of carnivorous habits among the Pyrrhocoridae are not at 

 all common. 



When the larvas are feeding the head quivers, there is a long heave up at 

 times which causes the stylets to lengthen and the bent part of the labium to 

 straighten (Plate XXIII, figs. 11, 12). The labium may be tucked away beneath 

 the body while the stylets still work in and out of the seed, bending and 

 shivering like fretsaw blades. 



The only observed breeding season commenced in August and lasted till De- 

 cember, coinciding with the cotton season. The earliest date recorded for finding- 

 couples in copulation was 28th August 1911, on ripening Hibiscus plants in the 

 Nursery at Ibadan. In March and April 1912, however, young forms from one 

 week upward in age were observed at Benin City, but the adults of this generation 



