Its habits resemble those of the flea. Indeed, should we compress its body strongly, it would bear a striking resemblance to that insect. It is evidently a connecting link between the flea, and the two winged flies. Like the former it lives on the body of its host, and obtains its food by plunging its stout beak into the bee and sucking its blood.
It has not been noticed in this country, but is liable to be imported on the bodies of Italian bees. Generally, one or two of the Braulas may, on close examination, be detected on the body of the bee; sometimes the poor bees are loaded down by as many as a hundred of these hungry blood-suckers. Assmuss recommends rubbing them off with a feather, as the bee goes in and out of the door of its hive.
Among the beetles are a few forms occasionally found in bees' nests and also parasitic on the body of the bee. Trichodes apiarius (Fig. 34, a, larva; b, pupa, front view) has long been known in Europe to attack the young bees. In its perfect, or beetle state it is found on flowers, like our Trichodes Nuttallii, which is commonly found on the Spiræa in August, and which may yet prove to enter our beehives. The larva devours the brood, but with the modern hive its ravages may be readily detected.
35. Meloë.
The Oil beetle, Meloë angusticollis (Fig. 35, male, differing from the female by having the antennæ as if twisted into a knot; Fig. 36, the active larva found on the body of the bee), is a large dark blue insect found crawling in the grass in the vicinity of the nests of Andrena, Halictus, and other wild bees in May, and again in August and September. The eggs are laid in a mass covered with earth at the root of some plant. During April and early in May, when the willows are in blossom, we have found the young recently hatched larvæ in considerable abundance creeping briskly over the bees, or with their heads plunged between the segments of the body, greedily sucking in the juices of their host. Those that we saw occurred on the Humble and other wild bees, and on various flies (Syrphus and Muscidæ), and there is no reason why they should not infest the Honey bee, which frequents similar flowers, as they are actually known to do in Europe. These larvæ are probably hatched out near where the bees hibernate, so as to creep into their bodies before they fly in the spring, as it would be impossible for them to crawl up a willow tree ten feet high or more, their feet being solely adapted for climbing over the hairy body of the bee, which they do not leave until about to undergo their strange and unusual transformations.
Early Stages of Meloë.
In Europe, Assmuss states that on being brought into the nest by the bee, they leave the bee and devour the eggs in the bee cells, and then attack the bee bread. When full-fed and ready to pass through their transformations to attain the beetle state, instead of at once assuming the pupa and imago forms, as in the Trichodes represented in fig. 34, they pass through a hyper-metamorphosis, as Fabre, a French naturalist, calls it. In other words, the changes in form which are preparatory to assuming the pupa and imago states are more marked and almost coequal with the larva and pupa states, so that the Meloë, instead of passing through three states (the egg, larva and pupa), in realty passes through these and two others in addition, which are intermediate. The whole subject of the metamorphosis of this beetle needs revision, but Fabre states that the larva, soon after entering the nest of its host, changes its skin and assumes a second larva form. Newport, who with Siebold has carefully described the metamorphoses of Meloë, does not mention this stage in its development, which Fabre calls "pseudo-chrysalis." It is motionless, the head is mask-like, without movable appendages, and the feet are represented by six tubercles. This is more properly speaking the semi-pupa, and the mature pupa grows beneath its mask-like form, which is finally moulted. This form, however, according to Fabre, changes its skin and turns into a third larva form (Fig. 37). After some time it assumes its true pupa form (Fig. 38), and finally moults this skin to appear as a beetle.
Fabre has also, in a lively and well-written account, given a history of Sitaris, a European beetle, somewhat resembling Meloë. He states that Sitaris lays its eggs near the entrance of bees' nests, and at the very moment that the bee lays her egg in the honey cell, the flattened, ovate Sitaris larva drops from the body of the bee upon which it has been living, and feasts upon the contents of the freshly laid egg. After eating this delicate morsel it devours the honey in the cells of the bee and changes into a white, cylindrical, nearly footless grub, and after it is full-fed, and has assumed a supposed "pupa" state, the skin, without bursting, incloses a kind of hard "pupa" skin, which is very similar in outline to the former larva, within whose skin is found a whitish larva which directly changes into the true pupa. In a succeeding state this pupa in the ordinary way changes to a beetle which belongs to the same group of Coleoptera as Meloë. We cannot but think, from observations made on the humble bee, the wasp, two species of moths and several other insects, that this "hyper-metamorphosis" is not so abnormal a mode of insect metamorphosis as has been supposed, and that the changes of these insects, made beneath the skin of the mature larva before assuming the pupa state, are almost as remarkable as those of Meloë and Sitaris, though less easily observed than they. Several other beetles allied to Meloë are known to be parasitic on wild bees, though the accounts of them are fragmentary.