DISEASES AND PESTS 93 



yellowish-brown, and has a small spine-like prominence 

 between the black antennae. The full-grown larva is 10 

 to 1 1 millimetres long and of a yellowish-white colour. 



In the related genus Promecotheca three species 

 are known as coco-nut pests, P. cumingii in the 

 Philippines, P. antiqua in New Guinea, and P. 

 opicicollis in the New Hebrides. The Philippine 

 species has been studied by Jones, 1 who describes it as 

 follows : 



The beetles vary from 7*5 to 10 millimetres in length, ex- 

 clusive of the antennae, and from 1*6 to 2 millimetres in width. 

 The thorax is much narrower than the slender body. General 

 colour brown ochre, head small, eyes and mandibles black, 

 elytra finely punctate in parallel furrows. Antennae 11-jointed, 

 tarsi broad and flat, one larger spine on inner side of each 

 femur with a corresponding depression on the tibia. The body 

 is pilose. 



The beetles are sluggish and do not fly readily upon being 

 disturbed. They rest by chnging lightly to the under side of 

 the leaf with the antennae extended forward close to the leaf. 

 They crawl about promiscuously on the leaves of the young 

 coco-nut and feed extensively upon the tissues between the 

 veins of the leaflets. The injury has the appearance of a slight 

 cut, but does not entirely penetrate the leaf. 



The damage done by the larva is greater than that by the 

 adult, as a single larva will excavate a place in the leaf from 

 12 to 16 millimetres long and 1J to 3 millimetres wide. 

 The tissue attacked soon dies and becomes brown, and in badly 

 infested areas the numerous dead leaflets give the palm the 

 appearance of being unhealthy or half dead ; where the trees 

 are used for decoration this effect is very displeasing. The 

 palm is also injured by the loss of these leaflets. 



The eggs are inserted by the female beetles just beneath 

 the epidermis of the leaf. They are deposited singly, and 

 hatch in from 13 to 15 days. The period of incubation varies 

 but little. The larvae upon hatching enter the parenchyma of 

 the leaf and here spend the entire larval period, which is about 

 32 days. They do not form any pupal cell, but pupate in the 

 middle of the excavated chamber formed by feeding. The 

 average length of the pupal stage is 7*5 days. The adult after 

 emergence remains from 2 to 4 days within the food chamber 

 before it bursts the epidermis of the leaf and escapes. 



Philippine Agricultural Review, May 1913. 



