INSECT LIFE

VIII

but then they do not expand, remaining always
crumpled, while, when the large piece of which the
sheaths are a part is pushed back by the move-
ments of the abdomen, they may be seen issuing
gradually from the sheaths, and immediately they
gain freedom, assuming dimensions out of all propor-
tion to the narrow prison from which they emerge.
They are then the seat of an abundant influx of
vital juices which swell and spread them out, and
the turgescence thus induced must be the chief
cause of their coming out of their sheaths. When
freshly expanded the wings are heavy, full of
moisture, and of a very light straw colour. If the
influx should take place in an irregular manner, the
point of the wing is seen to be weighed down by a
yellow droplet contained between its under and
upper surface.
After denuding itself of the abdominal sheath,
which draws away with it the wing-cases, the Sphex
again is motionless for about three days. During
this interval the wings assume their normal colour-
ing, the tarsi take colour also, and the mouth-parts,
at first spread out, assume their normal posi-
tion. After twenty-four days as a nymph the insect
attains its perfect state, tears its imprisoning cocoon,
opens a way through the sand, and appears one fine
morning in the light as yet unknown to it. Bathed
in sunshine, it brushes wings and antennae, passes its
feet again and again over its abdomen, washes its
eyes with its forefeet moistened with saliva, like a
cat, and, its toilette made, flies joyfully away. Two
months of life are before it.
Beauteous Sphegidae, hatched under my eyes