LIFE HISTORY OF INSECTS 83 



Many of the insects recorded do very little damage 

 in plantations ; principally because they occur in ex- 

 tremely limited numbers ; still, the fact must not be lost 

 sight of, that however small the injury caused by a 

 particular insect may be, it in all probability would be 

 augmented in direct ratio to its multiplication. 



Many insects pass through three stages of existence. 

 From eggs are hatched caterpillars or grubs. These 

 subsequently change to a pupal or resting stage, i.e. 

 chrysalis, from which the "perfect insect" (butterfly, 

 moth, or beetle) emerges. It is frequently in the " larval 

 or caterpillar stage " that a particular insect is most 

 destructive. Whenever a butterfly, moth, or beetle is 

 known to be the parent of a troublesome grub, every 

 possible means should be employed to destroy it. By 

 studying the life history of a destructive insect it is 

 sometimes possible to check its ravages by destroying 

 its eggs. 



Mosquito Blight, Helopeltis Antonii. This insect was 

 originally reported to destroy the young twigs and 

 leaves of the cocoa trees, but at the present time it appears 

 to be more destructive to the fruits. In a report upon 

 "Rubber, Cocoa, etc., in Ceylon, 1903," the writer has 

 given the following particulars regarding this pest. 

 ' The Helopeltis insect was described from Ceylon by a 

 French entomologist as far back as 1858, but it was not 

 until 1880 that it was reported as being destructive to 

 cocoa trees. The insect lays its eggs in the rind of the 

 cocoa fruit, where their presence is only evident by the 

 long white hairs which protrude from the end of each egg 

 in single pairs. In about nine or ten days the eggs 

 hatch out into small wingless insects, which grow rapidly 

 and eventually produce wings. These insects feed upon 

 the sap of the cocoa tree. At the point where the insect 

 punctures the fruit the tissues die, and where a large 

 number of these punctures occur close together on the 

 same fruit the diseased portions unite and the fruit dies. 

 In order to check this pest coolies are sent among the 

 cocoa trees armed with sticks smeared with the viscid 

 sap of the Jak tree, Artocarpus integrifolia ; on this the 

 wingless insects are caught, and so expert do the coolies 

 become at the work that one will catch as many as 

 1,500 insects per day. At one estate that I visited, 



