FAM I LY C URCULION I DAE 



425 



The egg is deposited on the upper surface to the left of the midrib at 

 the apex of the leaf in the case of the Hclideres, the left-hand side of the 

 leaf being then folded inwards down the main vein and rolled up, the edges 

 being tucked in. I did not observe the beetle ovipositing on the teak. 



TrIGON'OCOLUS. 



The genus contains an important pest of the padauk in the Andam m 

 Islands. 



Trigcnocolus subfasciatus, Fst. 



(Andaiiiaus Padauk Weevil.) 

 Habitat. — Andaman Islands. 



Tree Attacked. — Padauk (Pterocaypiis dalbcvgioidcs). Andamans (B. B. 

 Osmaston). 



Beetle.— Broadly elliptical, small, the rostrum thick and slightly 

 more than half length of body. Black, moderately shining ; under- 



surface greyish, due to the presence of a 

 Description. hne dense pubescence. Head small, eyes 



large, inserted on lower edges ; vertex 

 punc'ate ; rostrum long, thick, widest at upper end, curved down- 

 wards, punctate : antennae inserted two-thirds up, the scrobes 

 placed laterally, the antennal club large, elongate elliptical, pubes- 

 cent. Prothorax narrow in front, anterior margin straight, more 

 than twice as wide behind, sides rounded, disk finely and trans- 

 versely striate, anterior margin hnely punctate. Scutellum large, 

 transverse, punctate. Elytra wider than prothorax behind humeral FiG. 287. 



angles, latter obliquely truncate, sides constricted sharply towards Ti igonocoiits subfascia- 

 apex, apices separately rounded, exposing a small pygidium ; f"-^-, Fst. The Andamans 



striate and punctate, the punctures small, the mterspaces broad y\ "-"^ \' '^'' • 



, - . ^ „ Andaman Islands, 



and smooth. Length, 4.3 mm. to 4.7 mm. 



The attack of this small weevil pest on young padauk plants in the 

 Andaman Islands was first discovered and reported by 



Life History. Mr. B. B. Osmaston, now Conservator of Forests, then 



in charge of the forests of the islands. The insect made 

 its appearance in the tounggya padauk plantations, which were started near 

 Port Blair about 1903. PI. xxx shows the leading shoot of an unattacked 

 two-year-old padauk sapling. The damage done is caused by the mature 

 beetle, young shoots and leaders of seedlings and saplings being ringed by 

 the weevil, presumably to afford sustenance for its offspring in the dying 

 portion of the shoot. Plates xxxi to xxxv show the nature of the damage 

 done by the insect. 



In spite of careful search, however, Mr. Osmaston was unable to find 

 either the egg, larva, or pupa of the weevil. The beetles appear on the 

 wing chiefly in the wet months, Mr. Osmaston recording: "The damage is 

 chiefly done in wet months, April to October, during which period the 



