

204 Transactions. 



containing food) commencing in the first abdominal segment, to the end 

 of 6. A narrow dorso-lateral line on the last segment. Most of the internal 

 organs can be distinguished. Headpiece pale amber-brown, darker round 

 external margins, clypeal sutures, and mouth-parts. Head almost wholly 

 retracted into the prothorax. No true legs or prolegs, but protrusible 

 fleshy enlargements on the ventral surface of segments 2, 3, 4, 5, 6, 7, 

 and on the mesothorax and metathorax. The larva is cylindrical, slightly 

 flattened dorso- ventral] y. The mesothorax has the greatest diameter, then 

 the metathorax and segments 1 to 7, which are about equal ; 8, 9, 10 

 attenuated ; segment 9 about the shortest in the body ; segments not deeply 

 incised but evenly rounded. Ventral chain of fairly large somewhat 

 elongated grey diamond-shaped ganglia, quite distinct with double con- 

 necting bands, the thoracic ganglia larger and more elongated than the 

 abdominal ones. Cephalic ganglia dark grey, easily distinguished as back- 

 ward extensions of the head-capsule into the prothorax, and when the 

 head is retracted extend into the mesothorax and are not so easily dis- 

 tinguished. Head flattened, bluntly triangular. Skin covered with a fine 

 pile ; tubercles and setae present, setae comparatively long, the longer 

 ones being about two-thirds the length of their respective segments. The 

 details of the setal plan are left for a future j taper. The colour of the larva 

 when it leaves the mine is pale yellow throughout. The larva mines 

 dorsum uppermost. It can easily be seen in the mine by holding the leaf 

 up against the light. The frass-track ends abruptly, and the remainder 

 of the mine is filled by the light-coloured larva, its dark central line making 

 it at once consracuous. Even under ordinary circumstances a practised 

 eye can tell at once whether a mine is inhabited or not, by the nature of its 

 wider extremity ; in the empty mine this end is very light in colour and 

 in strong contrast to the remainder of the gallery, is devoid of frass, and 

 contains the conspicuous semicircular outlet cut by the escaped larva. In 

 inhabited mines the wider extremity is lighter in colour than the rest owing 

 to the absence of frass, the narrow dark central line of the larva taking 

 the place of this latter ; but most characteristic of all is the slightly domed 

 roof of this portion of the mine, caused by the larva within. The colour 

 of this part of the mine is a somewhat paler green than the rest of the 

 leaf-surface, whereas in the empty mine it is yellowish or light brown, light 

 grev, or very pale green, according to the length of time since it was vacated. 



The Cocoon. 



Somewhat ovate, mussel-shaped, ends rounded, anterior end slightly 

 flattened and broader than its nadir. The outlet of the cocoon is guarded 

 by a pair of flattened closely-applied lips extending across the whole front 

 of the cocoon. Length averaging 3 mm., width 2-2-5 mm., height 1-1-5 mm. 

 Colour at first whitish, changing to light green, to dark brown ; occasion- 

 ally the cocoons retain their green colour throughout. Interior of cocoon 

 whitish. Texture thin but dense, forming a kind of skin, and surrounded 

 outside, except where attached to external objects, by a small amount of 

 light floccy silk. Situated amongst dead herbage on the ground in the 

 neighbourhood of the food-plant. Two days are usually occupied in the 

 construction of the cocoon. After the last larval moult the cast skin remains 

 attached to the caudal end of the pupa ; in many other genera it is extruded 

 from the cocoon. Pupal period, of course, depends on local climatic condi- 

 tions. A number of specimens pupated 1st July, 1919, and emerged 8th 

 September, 1919 — seventy days ; another batch pupated 15th September, 



