25

The predominant game is the Praying Mantis, green; next comes the Grey
Mantis, ash-coloured. A few Empusae make up the total. The specimens
vary in dimensions within fairly elastic limits: I measure some which
are a third to a half inch long, averaging two-thirds to one inch long,
and some which are two-fifths, averaging three quarters. I see pretty
plainly that their number increases in proportion as their size
diminishes, as though the Tachytes were seeking to make up for the
smallness of the game by increasing the amount; none the less I find it
quite impossible to detect the least equivalence by combining the
two factors of number and size. If the huntress really estimates the
provisions, she does so very roughly; her household accounts are not at
all well kept; each head of game, large or small, must always count as
one in her eyes.

Put on my guard, I look to see whether the honey-gathering Bees have a
double service, like the game-hunting Wasps'. I estimate the amount of
honeyed paste; I gauge the cups intended to contain it. In many cases
the result resembles the first obtained: the abundance of provisions
varies from one cell to another. Certain Osmiae (O. cornuta and O.
tricornis (Cf. "Bramble-bees and Others": passim; and, in particular,
chapters 3 to 5.--Translator's Note.)) feed their larvae on a heap of
pollen-dust moistened in the middle with a very little disgorged honey.
One of these heaps may be three or four times the size of some other
in the same group of cells. If I detach from its pebble the nest of the
Mason-bee, the Chalicodoma of the Walls, I see cells of large capacity,
sumptuously provisioned; close beside these I see others, of less
capacity, with victuals parsimoniously allotted. The fact is general;
and it is right that we should ask ourselves the reason for these marked
differences in the relative quantity of foodstuffs and for these unequal
rations.

I at last began to suspect that this is first and foremost a question of
sex. In many Bees and Wasps, indeed, the male and the female differ not
only in certain details of internal or external structure--a point of
view which does not affect the present problem--but also in length and
bulk, which depend in a high degree on the quantity of food.

Let us consider in particular the Bee-eating Philanthus. Compared with
the female, the male is a mere abortion. I find that he is only a third
to half the size of the other sex