Agriculture Reference
In-Depth Information
instars. The cases of first-instar larvae are usually
formed from sand grains; those of subsequent
instars are constructed from pieces of watercress
leaves and petioles, but fourth- and fifth-instar
larvae usually revert to using sand grains. Most
larvae are fully grown by the following May or
June. Each then pupates within its case. There is
just one generation annually.
transparent centrally;
hindwings
mainly trans-
parent;
fore tibiae
each with a single spur;
abdo-
men
often appears green (in male) or yellow (in
female), owing to the underlying fat-
body tissue. Egg 0.4 x 0.3 mm, elliptical, trans-
lucent-yellow.
Larva
up to 17 mm long;
head
yellowish-brown with darker markings;
thorax
pale chestnut-brown to yellowish-brown, with
darker markings;
abdomen
white.
Case
up to
23 mm long; composed either of sand grains
or of cut-out pieces of watercress, cemented
together.
DESCRIPTION
Adult
28 mm wingspan;
forewings
angular, yel-
lowish-brown, suffused with brown and partly
