olouring and the little nipple constituting the head
reveal to us the larva of the Anthrax, which does not concern us at
present; in the other, the general structure and appearance betray the
grub of some Hymenopteron. The Mason's second exterminator is, in fact,
a Leucopsis (Leucopsis gigas, FAB.), a magnificent insect, stripped
black and yellow, with an abdomen rounded at the end and hollowed out,
as is also the back, into a groove to contain a long rapier, as slender
as a horsehair, which the creature unsheathes and drives through the
mortar right into the cell where it proposes to establish its egg.
Before occupying ourselves with its capacities as an inoculator, let us
learn how its larva lives in the invaded cell.

It is a hairless, legless, sightless grub, easily confused, by
inexperienced eyes, with those of various honey-gathering Hymenoptera.
Its more apparent characteristics consist of a colouring like that
of rancid butter, a shiny and as it were oily skin and a segmentation
accentuated by a series of marked swellings, so that, when looked at
from the side, the back is very plainly indented. When at rest, the
larva is like a bow bending round at one point. It is made up of
thirteen segments, including the head. This head, which is very small
compared with the rest of the body, displays no mouth-part under
the lens; at most you see a faint red streak, which calls for the
microscope. You then distinguish two delicate mandibles, very short and
fashioned into a sharp point. A small round mouth, with a fine piercer
on the right and left, is all that the powerful instrument reveals. As
for my best single magnifying-glasses, they show me nothing at all. On
the other hand, we can quite easily, without arming the eye with a lens,
perceive the mouth-apparatus--and particularly the mandibles--of
either a honey-eater, such as an Osmia, Chalicodoma or Megachile, or
a game-eater, such as a Scolia, Ammophila or Bembex. All these possess
stout pincers, capable of gripping, grinding and tearing. Then what
is the purpose of the Leucopsis' invisible implements? His method of
consuming will tell us.

Like his prototype, the Anthrax, the Leucopsis does not eat the
Chalicodoma-grub, that is to say, he does not break it up into
mouthfuls; he drains it without opening it and digging into its vitals.
In him again we see exemplified that marvellous art which consists in
feeding on the victim without killing it until the meal is over