THE FAUNA OF THE CACAO FIELD 117 



red band extending across the abdomen." (Pamphlet 

 No. 58, Imperial Department of Agriculture.) The insects 

 are found on the pods and leaves of cacao in groups or 

 colonies, the location of which is indicated by a discoloured 

 area arising from the wounds made by the insect while 

 feeding. When the attack is severe the injury to the leaf 

 is sometimes sufficient to cause it to fall from the tree, and 

 when an attack becomes general on an estate short crops 

 result. The attack on the pods causes an 

 amount of discoloration which renders it 

 difficult to determine without close exam- 

 ination whether the pod is fit for picking 

 or not, and many pods are picked by 

 the inexperienced which prove immature 

 and useless. 



In Trinidad the attack of this, or like 

 insect, has not been of an important cha- 

 racter to date (1911), but several species of 

 the order are known to be present, and 

 may be found on mature flowers of hibiscus, °'( ^ 25)! ^^ 

 rose, and other plants in considerable 

 numbers. The damage done to plants by this class of 

 insect is well known to those who have had the oppor- 

 tunity of gaining experience of the " hot house " culti- 

 vation of temperate climates. There " thrip " (used as 

 singular and plural) is dealt with by tobacco smoke, to- 

 bacco water, and by the maintenance of a continuous 

 humidity of the atmosphere. In Grenada where the worst 

 attack has been experienced, cacao is grown mostly without 

 shade, and the atmosphere is dry, in general. In Trinidad, 

 shade is used and the humidity of the climate is greater, 

 and " thrip " has as yet given little cause for alarm. The 

 inference to be drawn appears to the author to be an 

 obvious one in favour of shade for cacao. A parasitic 

 fungus has been found an effective control for " thrip " 

 on pear-trees in California. For control in Grenada, 

 wash of whale-oil soap, kerosine emulsion, and rosin wash 

 are recommended. An invasion of " thrip " in large 



