Series IV. Cyclorrhapha Schizophora: Stomoxys, Haematobia; both sexes (?); larvae in dung. [The Tse-tse flies, Glossina, are placed in this family, though their mode of parturition is that of the next section].
Series V. Pupipara. The habit of blood-sucking is probably common to all the group and to both sexes. The flies, with one exception, frequent Vertebrates; in many cases living entirely on their bodies, and apparently imbibing much blood; the larvae are nourished inside the flies, not on the imbibed blood, but on a milky secretion from the mother.
Sub-Order Aphaniptera. Fleas. The habit of blood-sucking is common to all the members and to both sexes. The larvae live on dried animal matter.
Fossil Diptera.—A considerable variety of forms have been found in amber, and many in the tertiary beds; very few members of the Cyclorrhaphous Sections are, however, among them; the Tipulidae, on the other hand, are richly represented. In the Mesozoic epoch the Order is found as early as the Lias, the forms being exclusively Orthorrhaphous, both Nemocera and Brachycera being represented. All are referred to existing families. Nothing has been found tending to connect the Diptera with other Orders. No Palaeozoic Diptera are known.
Series 1. Orthorrhapha Nemocera
Fam. 1. Cecidomyiidae.—An extensive family of very minute and fragile flies, the wings of which have very few nervures; the antennae are rather long, and are furnished with whorls of hair. In the case of some species the antennae are beautiful objects; in Xylodiplosis some of the hairs have no free extremities, but form loops (Fig. 220). In the males of certain species the joints appear to be double, each one consisting of a neck and a body. Although comparatively little is known as to the flies themselves, yet these Insects are of importance on account of their preparatory stages. The larvae have very diverse habits; the majority live in plants and form galls, or produce deformations of the leaves, flowers, stems, buds, or roots in a great variety of ways; others live under bark or in animal matter; some are predaceous, killing Aphidae or Acari, and even other Cecidomyiids.
Fig. 219—Cecidomyia (Diplosis) buxi. Britain. A, Larva, magnified; B, pupa; C, imago; D, portion of antenna. (After Laboulbène.)
Fig. 220—One segment of antenna of Xylodiplosis sp.; a, Tip of one segment; b, base of another. (After Janet.)