Let us look at the Sphex at work in flat ground, as is much more frequently the case. As soon as the burrow is hollowed out, the chase begins. Let us profit by the absence of the Hymenopteron in search of game, and take a look at her dwelling. The spot chosen by a Sphex colony is generally horizontal, though the ground is not so level but that there are little mounds crowned by a tuft of grass or thrift, or inequalities consolidated by the slender roots of the vegetation which covers them. It is on the sides of such furrows that the Sphex places her den. For two or three inches in depth the gallery is horizontal, serving as an approach to the hidden shelter for the provender and the larvæ. In this vestibule the Sphex takes refuge in bad weather, rests there at night, and occasionally by day for a few instants, showing only her expressive face and impudent eyes. Beyond the vestibule an abrupt turn descends more or less obliquely to a depth of two or three inches more, ending in an oval cell rather larger in diameter, whose axis lies parallel with the horizontal gallery. The cell walls are not covered with any particular cement, but in spite of their bareness they have evidently been the object of most careful labour. The sand is heaped and levelled on the floor, on the ceiling, and sides, so as to do away with the risk of landslips, or any roughness which might injure the delicate skin of the larva. This cell communicates with the passage by a narrow entrance, just wide enough to allow the Sphex, burdened with prey, to enter. When this first cell is furnished with an egg and necessary provisions, the Sphex walls up the entrance, but does not yet abandon her burrow. A second cell is hollowed beside the first, and provisioned in the same manner; there is then a third made, and sometimes a fourth. Only then does the Sphex cast back into the burrow the rubbish heaped at the entrance, completely effacing all outward trace of her work. Three cells are usually found in each burrow, rarely two, and yet more rarely four. As one learns by dissecting the insect, one may estimate the number of eggs laid at about thirty, which would make the number of burrows needed ten. Now these are hardly begun before September, and are finished before the end of the month. Consequently the Sphex cannot devote more than two or three days at most to each burrow and its stores. Evidently the active little creature has not a minute to lose, when in so short a time she has to hollow out the lair, procure a dozen crickets, sometimes brought from a distance through endless difficulties, to store them, and finally to stop up the burrow. Moreover, there are days when wind makes hunting impossible; rainy days or overcast ones suspending all work. The Sphex cannot give to her building the enduring solidity that Cerceris tuberculata gives to its deep galleries. This species transmit their solid abodes from one generation to another, each year hollowed more