Cecidomyiidae | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Diptera |
Suborder: | |
Infraorder: | Bibionomorpha |
Superfamily: | Sciaroidea |
Family: | Cecidomyiidae |
Subfamilies | |
Synonyms | |
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Cecidomyiidae (sometimes spelled Cecidomyidae) is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls.
Cecidomyiidae are very fragile small insects usually only 2–3 mm (0.079–0.118 in) in length; many are less than 1 mm (0.039 in) long. They are characterised by hairy wings, unusual in the order Diptera, and have long antennae. More than 6,000 species and 783 genera are found worldwide, but since 1,100 are from well-studied North America, this may be an underestimate.
Cecidomiidae are minute to small (0.5-3.0 mm), rarely larger (up to 8 mm, wing length 15 mm) flies with a delicate appearance. Except for a few genera with reduced wings, the eyes are holoptic. The mouthparts are reduced. Cecidomiid antennae are notably long, with 12-14 segments, (sometimes fewer and up to 40 in some genera). The antennal segments either consist of a basal thickening and petiole or they are binodal, with a proximal node, an intermediate petiole and a distal node. Basal, medial, and apical whorls of hairs occur on the antennal segments. In some species, whorls of loop-shaped sensory filaments are also found, the basal or medial one sometimes being reduced. Some gall flies have only one (basal) whorl of hairs on the antennal segments, and the sensoria (transparent sensory appendages) differ in size and shape. The filaments are thread-like in the Porricondylinae and in all the Cecidomyiinae and take the form of long loops in the supertribe Cecidomyiidi). Ocelli are present only in the Lestremiinae. The wings are usually clear, rarely patterned. The wing bears microtrichia, often as scales, and some species have macrotrichia. The number of longitudinal veins is reduced. Only veins R1, R4+5, M3+4 and Cu1 are well developed in most species. The medial veins M1 and M2 are developed only in primitive groups, and the costa usually has a break just beyond vein R5. The legs are long and slender, without apical bristles.
Catochini wing veins
Cecidomyiinae wing veins
Lasiopterini wing veins
Lestremiini wing veins
Micromyini and Peromyiini wing veins
Porricondylinae (most) wing veins
Winnertziini wing veins
The genitalia of males consist of gonocoxites, gonostyles, aedeagus, and tergites 9 and 10. Lower (in the evolutionary sense) gall flies often have sclerotized parameres and a more or less transparent plate (the tegmen) located above theaedeagus-the tegmen. In higher gall flies, the parameres and tegmen are not developed. In these, instead, close to the aedeagus, is a triangular basal outgrowth of the gonocoxites called the gonosterna. Supporting structures called apodema are located near the base of the genitalia in males; these are often equipped with two outgrowths. The ovipositor is short, lamelliform, or long, mobile, and in some species, acicular.