Fig. 41.—Sapyga 5-punctata ♀, Britain.
The economy of Sapyga, the only genus, has been the subject of difference of opinion. The views of Latreille and others that these species are parasitic upon bees is confirmed by the observations of Fabre, from which it appears that S. 5-punctata lives in the burrows of species of the bee-genus Osmia, consuming the store of provisions, consisting of honey-paste, that the bee has laid up for its young. According to the same distinguished observer, the Sapyga larva exhibits hypermetamorphosis (i.e. two consecutive forms), and in its young state destroys the egg of the bee; but his observations on this point are incomplete and need repetition. We have two species of Sapyga in Britain; they differ in colour, and the sexes of S. 5-punctata also differ in this respect; the abdomen, spotted with white in both sexes is in the female variegate with red. Smith found our British Sapyga 5-punctata carrying caterpillars.
Sub-Fam. 5. Rhopalosomides.—Antennae elongate, spinigerous; ocelli very prominent; tarsi of peculiar structure, their claws bifid.
Fig. 42—Rhopalosoma poeyi. A, female imago; B, front of head. Cuba. (After Westwood.)
This sub-family has recently been proposed by Ashmead[[47]] for an extremely rare American Insect that had previously been placed by Cresson among parasitic Hymenoptera. Westwood classed Rhopalosoma among Diploptera, saying of it "animal quoad affinitates excrucians." We reproduce Westwood's figure, but not being acquainted with the Insect we can express no opinion as to whether it is allied to the Scoliidae or to the Sphegidae. The habits are, we believe, quite unknown.
Fam. 2. Pompilidae.
Pronotum at the sides reaching the tegulae; hind body never definitely pedicellate, though the first segment is sometimes elongate and conical; hind legs long; eyes elliptic in form, not emarginate.
The Pompilidae are perhaps the most extensive and important of the groups of Fossores, and are distributed over all the lands of the globe, with the exception of some islands and of the inclement arctic regions. The sting of the Pompilidae, unlike that of most of the Fossores, inflicts a burning and painful wound; the creatures sometimes attain a length of two or three inches, and a sting from one of these giants may have serious results. Although there is considerable variety in the external form of the members of the group, the characters given above will enable a Pompilid to be recognised with approximate certainty. The elongation of the hind legs includes all the parts, so that while the femur extends nearly as far back as the extremity of the body—in dried examples at any rate—the tibiae and the long tarsi extend far beyond it; thus these Insects have great powers of running; they are indeed remarkable for extreme activity and vivacity. They may frequently be seen running rapidly on the surface of the ground, with quivering wings and vibrating antennae, and are probably then employed in the search for prey, or some other of the operations connected with providing a store of food for their young. Spiders appear to be their special, if not their only, prey. Several authors have recorded details as to the various ways in which the prey is attacked. Fabre has observed the habits of several species, and we select his account of the modus operandi of species of the genera Pompilus and Calicurgus, in their attacks on poisonous spiders that inhabit holes in the ground or in walls. The wasp goes to the mouth of the spider's burrow, and the latter then dashes to the entry, apparently enraged at the audacity of its persecutor.