PROCEEDINGS OE THE TIIinD ENTOMOLOGICAL MEETING 040 



of the wings is 27 — 30 mm. The male moth probably appears usually 

 in March and April, according to my investigation last year. Occasion- 

 ally, when this pest is allowed to spread, it may become exceedingly 

 serious. An attack is on record where on an experiment garden in 

 Anpeichin every leaf on a block of about an acre was destroyed in the 

 manner described above. This may be, however, not a permanent 

 character, and the damage done by this insect is usually inferior to that 

 of Clania destnictor. 



The most convenient control-measure is hand-picking the cases 

 during the early spring. Up to the present time, only two parasites, 

 one being a rather small Tachinid fly. the other a small Ichneumon 

 fly, have been reared from the larval case. 



No. 24. — Diabasis {?) sp. (Taiwan-Chibi-Miuoga.) 



This small Psychid is commonly foimd in May, throughout Taiwan 

 Island, but its occurrence is not abundant, and consequently this is the 

 least serious of the Psychid pests of tea in Formosa. 



The larval cases of this species might be described as small thorns 

 about 10 — 12 mm. long, of a dull grey colour, somewhat pointed at the 

 apex and shghtly widened below but not into a circular sucker-like 

 mouth. They are always covered with many small fragments of tea- 

 leaf or thin bark, but never carry pieces of twigs attached to them. 

 The caterpillars attack the lower or sometimes the upper side of the 

 leaf and the twigs, and eat irregular circular spots at the margins, but 

 when they are quite young they eat the lower epidermis in irregular 

 shape. They move from place to place until they reduce the leaf to 

 a mass of veins with some green surface. After the leaves and the buds 

 have all been destroyed, they come down to attack the bark and eat 

 the surface of it. There is a countless multitude of these creatures all 

 ■over the bush and within a few weeks it is damaged almost beyond 

 repair without very heavy pruning, but this only happened in one 

 case which I met in Koshun in the last year. 



The full-grown caterpillar is about 8 mm. long or more, and 

 is brownish except the head and thorax which are dull yellowish ; the 

 head and thorax have a few inconsjjicuous blackish brown flecks, and 

 each segment of the abdomen bears about 8 tubercles from which arise 

 fine hairs. 



When full-grown the caterpillars almost always firmly fasten their 

 cases on the twigs, and hang down by means of rather stout, about 

 5 mm. long, dull-grey prolongations of the case. At that time the shape 

 of the cases almost always become slender but they still retain their 

 conical shape. The pupa of the male is castaneous, and is 7 — 8 mm 



