of its building, a narrow dormer-window just large enough to allow its
slender neck to pass. When the store has been taken in, this accessory
orifice, which is used only during the last few moments, is closed with a
mouthful of mortar, thrust outward from within. This forms the irregular
nipple which projects from the side of the shell.

For the present I shall not expatiate further upon Stizus ruficornis, whose
complete biography would be out of place in this chapter. I will limit
myself to mentioning its method of constructing strong-boxes in order to
compare it with that of the Bembex and above all with that of the Tachytes,
a consumer, like itself, of Praying Mantes. From this parallel it seems to
me to follow that the conditions of life in which men see to-day the origin
of instincts--the type of food, the surroundings amid which the larval life
is passed, the materials available for a defensive wrapper and other
factors which the evolutionists are accustomed to invoke--have no actual
influence upon the larva's industry. My three architects in glued sand,
even when all the conditions, down to the nature of the provisions, are the
same, adopt different means to execute an identical task. They are
engineers who have not graduated from the same school, who have not been
educated on the same principles, though the lesson of things is almost the
same for all of them. The workshop, the work, the provisions have not
determined the instinct. The instinct comes first; it lays down laws
instead of being subject to them.


CHAPTER 7. CHANGE OF DIET.

Brillat-Savarin, when pronouncing his famous maxim, "Tell me what you eat
and I will tell you what you are," certainly never suspected the signal
confirmation which the entomological world would bestow upon his saying.