It is the same Fly that caused the Bembex such lively fears by lying in ambush near the burrow. The Wasp’s terror is but too well founded. This is what happens inside the dwelling: around the heap of food which the mother exhausts herself in keeping up to the requisite quantity, seated in company with the lawful offspring, are from six to ten hungry guests, who dip their sharp-pointed mouths into the common dish with no more restraint than if they were at home. Harmony seems to prevail at the table. I have never seen the lawful larva grow indignant at the indiscretion of the alien grubs, nor have I seen these appear to wish to interfere with the other’s repast. All help themselves indiscriminately and eat away peaceably without seeking a quarrel with their neighbours. So far all would be well, if a serious difficulty did not now arise. However active the mother-nurse may be, she is obviously not equal to such an output. She had to be constantly hunting to feed one larva, her own; how could she possibly manage to provide for a dozen greedy mouths? The result of this enormous increase of family can only be want, or even starvation, not for the Fly’s maggots, which, developing more quickly than the Bembex’ larva, get ahead of it and profit by the days when there is still plenty for everybody, as their host is too young to need much, but certainly for that unfortunate host, who arrives at the transformation period without being able to make up for lost time. Besides, even if the first visitors, in becoming pupæ, leave him the free run of the table, others appear upon the scene, so long as the mother continues to come to the nest, and complete his starvation. In burrows invaded by numerous parasites, the Bembex’ larva is in point of fact much smaller than one would suppose from the heap of food consumed, the remains of which encumber the cell. Limp, emaciated, reduced to a half or a third of its normal size, it vainly tries to weave a cocoon for which it does not possess the silk; and it perishes in a corner of the house among the pupæ of its more fortunate companions. Its end may be more cruel still. Should the provisions fail, should the mother-nurse delay too long in returning with food, the Flies devour the larva of the Bembex. I verified this black deed by rearing the brood myself. All went well so long as there was plenty to eat; but, if the daily portion was omitted by accident or design, next day or the day after I was sure to find the Fly’s grubs greedily slicing up the larva of the Bembex. So, when the nest is invaded by the parasites, the lawful larva is doomed to perish, either by hunger or by a violent death; and this is what makes the Bembex hate the sight of the Miltogrammæ prowling around her home.