This tiny worm, the first form or “primary larva” of the Anthrax, is very active. It tramps over the fat sides of its victim, walking all round it. It covers the ground pretty quickly, buckling and unbuckling by turns, very much after the manner of the Looper-caterpillar. Its two ends are its chief points of support. When walking it swells out, and then looks like a bit of knotted string. It has thirteen rings or segments, including its tiny head, which bristles in front with short, stiff hairs. There are four other pairs of bristles on the lower surface, and with the help of these it walks. For a fortnight the feeble grub remains in this condition, without growing, and apparently without eating. Indeed, what could it eat? In the cocoon there is nothing but the larva of the Mason-bee, and the worm cannot eat this before it has the sucker or mouth that comes with the second form. Nevertheless, as I said before, though it does not eat it is far from idle. It explores its future dish, and runs all over the neighborhood. Now, there is a very good reason for this long fast. In the natural state of the Anthrax-grub it is necessary. The egg is laid by the mother on the surface of the nest, at a distance from the Bee’s larva, which is protected by a thick rampart. It is the business of the new-born grub to make its way to its provisions, not by violence, of which it is incapable, but by patiently slipping through a maze of cracks. It is a very difficult task, even for this slender worm, for the Bee’s masonry is exceedingly compact. There are no chinks due to bad building, no cracks due to the weather. I see but one weak point, and that only in a few nests: it is the line where the dome joins the surface of the stone. This weakness so seldom occurs that I believe the Anthrax-grub is able to find an entrance at any spot on the dome of the Bee’s nest. The grub is extremely weak, and has nothing but invincible patience. How long it takes to work its way through the masonry I cannot say. The work is so laborious and the worker so feeble! In some cases I believe it may be months before the slow journey is accomplished. So it is very fortunate, you see, that this first form of the Anthrax, which exists only in order to pierce the walls of the Bees’ nest, should be able to live without food. At last I saw my young worms shrink, and rid themselves of their outer skin. They then appeared as the grub I knew and was so anxiously expecting, the grub of the Anthrax, the cream-colored cylinder with the little button of a head. Fastening its round sucker to the Bee-grub, it began its meal. You know the rest.