164 | December, 
not as yet common in British collections, I thought that some account of its larval 
state might not be unacceptable, and for this purpose have now put together the 
results of my investigations carried on during the present year. 
The egg state I have not yet observed, and will not ‘obtrude any guess as to 
when or where it is laid; the young larva, when less than one quarter of its full 
growth, mines within the stem of Salsola Kali, generally in the side shoots; bu+ 
when it has reached half growth, it seems to change its abode, and to go outside 
and attack the unripe seeds, and then setting out from the cavity thus made, to 
burrow into the main stem, where it continues to feed in concealment until nearly 
fully grown: during this period of its existence its presence may be detected in the 
following manner: it protects the entrance hole of its burrow with a few exceed- 
ingly fine silk threads, and should a rainy day be succeeded by a high wind, these 
threads will retain many particles of sand blown over them whilst yet damp, and 
will thus become much more conspicuous than when in their more usual condition. 
When the larva is near its full growth, it ceases to mine, and coming outside 
weaves for itself a delicate cylindrical web, in which it lies, often, however, chang- 
ing its position, and sometimes trusting for protection only to its resemblance in 
colour to the stem on which it lies stretched out ; when once in its web, it is not 
easily dislodged, and if driven out, still hangs on by a short thread, and soon 
returns again if not further disturbed. When full grown it enters the sand, and 
there constructs a cocoon of the surrounding particles, sometimes attaching it to a 
stone. 
The youngest example of the larva, that I found, was less than a quarter of an 
inch long; of a pale semi-transparent glaucous green colour, with a black head and 
plate behind it. With growth the colour changes to an opaque cchreous-green, or 
to an olive-green, sometimes to a reddish-grey, the black head and plate continuing 
as long as the larva mines within the plant. 
The full grown larva is five-eighths of an inch in length, slender, tapering 
from the back of the second segment to the head, which is partly retracted within it ; 
the second segment is quite as long as anyof the others; the body tapers also a little 
gradually from the tenth tothe anal tip; on the thoracic segments there are deeply 
defined wrinkles, but on the others there are only one deep subdividing wrinkle, 
and another very slight one near the segmental division; all the legs small, and 
well under the body, which is cylindrical though just a trifle flattened on the back 
and belly. In colour the head is pale brownish-ochreous, marked on each lobe 
more or less with blackish-brown, the plate on the second segment is shining, and 
often faintly edged at the side with a slight streak of blackish, and is generally 
rather more inclining to ochreous, but is otherwise similar to the rest of the body 
in markings ; the ground colour is generally of a glaucous green tint, deeper on 
the back and sides, and paler on the belly and legs; the dorsal line is a deep pink, 
or dark green, very faintly edged with a fine line of paler green than the ground 
colour; the sub-dorsal line is distinctly paler whitish-green, the line just above the 
spiracles is similar, and the space between them is a broad stripe of glaucous-green, 
darker than the ground; just beneath the sub-dorsal line, on the third and twelfth 
segments, is an ocellated spot of pale flesh-colour encircled with black ; the minute 
spiracles are of the ground colour delicately outlined with brown; the tubercular 
dots are brown, but are scarcely visible without the help of a lens, nor are the fine 
