648 



the ground, as tbey are by no means so firmly attached as C. viridis ; 

 it seems to thrive best in the shade. Owing to the enormous numbers 

 in which it may be present, the damage done by the white scale is far 

 greater than that by the green. Lawana Candida, which is used as a 

 shade tree, Manihot glaziovii, Leucaena glauca, Hevea brasiliensis, 

 Ceara rubber and dadap (Erythrina lithosperma) are also attacked. 

 Three CoccineUids, one of them probably Scymnus bipnnctatus, a 

 species of Chrysopa, two Chalcids and a Cecidomyiid, perhaps Diplosis 

 acarivora, Zehnt., are mentioned as preying on this scale, but their 

 effect as tested experimentally on an infested plant was relatively 

 small. This scale does not appear to be associated with ants, which 

 seem to avoid the waxy threads which surround it. The outbreaks 

 are thought to begin on the lamtoro (Lawana) shade-trees and then 

 spread to the coffee. Leucaena is an imported tree which the scale 

 has found suitable as a food-plant. As it appears to attack the healthiest 

 trees by preference, special manuring is of no avail against it. Lawana 

 Candida should be abandoned as a shade tree and Jjencaena, near coffee 

 plantations, should be destroyed. The only insecticide suggested is 

 prepared as follows:- — 2| lb. tobacco is well boiled in a gallon of 

 water and the extract filtered, 1 lb. of soft soap is then dissolved in 

 the liquor and, for use, 20 times the volume of water is added ; 

 spraying should be done on a sunny day and repeated in 2 or 3 weeks. 

 This gave good results in the laboratory. 



Pseudococcus eUn is a pest of Coffea robusta. A brief description of 

 the insect is given ; it is probably not a serious pest, though the 

 damage done is difficult to determine, as it is almost always in the 

 company of P. hicaudatus. A bibliography of 37 works concludes 

 this paper. 



Janssens ( — ). La culture du Manihot glaziovii t la Station Agricole 

 de I'Etat ^ Bokala (Moyen Congo). [The cultivation of Manihot 

 glaziavii at the State Agricultural Station at Bokala, Middle 

 Congo.]— Bidl. Agric. Congo Beige, Londori, v. no. 3, September 

 1914, pp. 416-456, 11 figs. 6 diagrams. [Received 11th September 

 1915.] 



Among the insect enemies of Manihot glaziovii which occur at 

 Bokala, Middle Congo, are Pseudococcus sp.- — probably P. adonidum — 

 three species of Coleoptera (not specified) and termites. 



Maynk (R.). Les Ennemis de rH6v6a au Congo Beige. [Hevea pests 

 in the Belgian Congo.] — Bull. Agric. Congo Beige, London, v., 

 No. 4, December 1914, pp. 577-596, 8 figs. [Received 15th 

 October 1915.] 



Since 1912, the relative freedom from insect pests which Hevea had 

 enjoyed in the Congo no longer obtains. The species attacking it are 

 of native origin, and while their importance is not great at present, 

 they require immediate attention in view of the risks involved. The 

 Cerambycid, Mallodon [Stenodontes) downesi, Hope, chiefly attacks 

 Manihot glaziovii ; the larvae mine the wood, excavate a nymphal 

 chamber near the bark and complete their life-cycle there. Injured 

 trees are easily knocked down by a storm and the fallen trees furnish 

 most favourable breeding places for the beetles. 31. downesi has been 



