214 



Transactions. 



green ; 

 gments 



Head 

 in any 



linear 



notice - 



of the 



mines 



The Larva. 



Length when fully fed, 4-5 mm. Ground-colour bright grass- 

 dorsal band yellowish-brown, more greenish in younger larvae. Se 

 not deeply incised ; body cylindrical, caudal attenuation gradual, 

 light amber-brown. Cephalic ganglia and ventral chain not noticed 

 specimens. Prolegs as in other Nepticulid larvae. The dorsal 

 structures in segment 10 are situated caudo-laterad and are not very 

 able dorsally. Setae relatively short, about one-third the length 

 corresponding segment. Body-pile relatively coarse. The larva 

 dorsum uppermost. 



The Cocoon. 



This is of the same shape as that of N. ogygia ; mussel-shaped, with 

 flattened anterior lip. Constructed of fine silk closely woven to form a thin 

 weatherproof skin. Average size, 2 mm. by 2-5-3 mm. Is surrounded by 

 a scanty amount of loose silk. The cocoons are spun amongst dead herbage 

 around the food-plant, a favourite place being between the stem and the 

 base of the leaf-stalk of the food-plant itself. Colour on construction white, 

 changing to green and later to dark brown. All cocoons found in the open 

 were brown, whereas the great majority constructed in captivity in a dry 

 box were white or very pale green, and these when placed in a moist 

 atmosphere weeks later turned brown within twelve hours, so there is no 

 doubt that moisture affects the colour of the silk. In captivity a number 

 of cocoons were very minute, being only about half the normal size ; these 

 were most likely constructed by poorly nurtured larvae, since it was not a 

 matter of difference of sex. The imagines in these cases were very minute. 

 The larva remains dormant in the cocoon for about a week before the final 

 moult. 



The Pupa. 

 Ventral view : Front prominent, bluntly rounded in the male, somewhat 

 bluntly pointed in the female. Last segment usually hidden behind the 

 caudal extremities of the third legs and forewings. Eye two-thirds covered 

 by the basal joint of the antenna and maxillary palp. Maxillary palpus 

 reaching from the antennae to the labrum, of which it sometimes falls rather 

 short ; covers the caudal margin of the eye. Labial palpus narrow, extends 



slightly farther caudad than the maxillae. 

 Maxillae triangular, with the base against the 

 lower border of the maxillary palpus. First 

 legs stout, broadest in their upper half, extend 

 as far as the caudal extremities of the second 

 coxae in both sexes. The femur occupies a 

 small narrow slip separating the upper extremity 

 of the first leg from the maxilla, more notice- 

 able in the male. Second legs reach to about 

 half-way between the caudal extremities of the 

 first and second, their narrowed cephalic, ex- 

 tremity reaching the lower border of the maxillary 

 palp. The second tibiae do not appear ; the 

 Fig. 12.— Pupa of N. tricentra. third appear only very slightly from beneath 

 To scale. the tips of the second legs. Third legs meet- 



ing in the mid-line shortly after appearing 

 from under the antennae lateral to the extremities of the second legs, 

 thereafter extend in both sexes as far as the lower border of the last abdominal 



