Key To The Identification of Families of
Parasitic and Predatory Diptera
(Derived from V. A. Trjapitzin, 1982 by S. V. Trjapitzin & E. F. Legner)
[This key is in a form commonly used in Eastern Europe. If the statement is true, proceed to the next line, whereas if it is false, go to the line shown in parentheses]
(Note: Illustrations are of species from various geographic areas):
1 (28). Antennae with 3 segments, segment 3 mostly markedly different from other segments in shape and size, sometimes ring-like .......... suborder Brachycera
2 (5). Group of rather large hypopleural setae above hind coxae present; wings with a short anal cell, M in apical half usually (but not always) curved in an angle, so that a formed apical transverse vein limits posterior cell 1 externally; thorax and abdomen usually covered with thick setae; if setae lacking, then abdomen almost globular .......... Tachinidae <Habits>; <Adults> & <Juveniles> (Phasiinae)
3 (4). Postscutellum present; larvae endoparasitic in different insects: Hemiptera, Coleoptera and their nymphs and larvae respectively, larvae of Lepidoptera and sawflies, etc. ......... Tachinidae <Habits>; <Adults> & <Juveniles>
4 (3). Postscutellum absent; flies usually gray, with light silver spots; larvae predaceous on larvae and pupae of Lepidoptera and sawflies, in egg sacs of locusts, parasitic in bodies of locusts, beetles, bugs, flies and various Lepidoptera ......... Sarcophagidae <Habits>; <Adults> & <Juveniles>
5 (2). Group of rather large hypopleural setae above hind coxae absent.
6 (7). Wings without transverse veins; veins along anterior margin strongly sclerotized, thick, only slightly marked as faint lines on the rest of wing blade; small (usually 1-3 mm long) hump-backed flies; larvae of many species parasitic in adult insects and insect larvae ........... Phoridae <Habits>; <Adults> & <Juveniles>
7 (6). Wings with transverse veins; rate of sclerotization of veins on anterior and posterior parts of wing more or less the same
8 (17). Anal cell open; if closed, then long, with a long stalk
9 (10). Three pulvilli on tarsi under claws; wings with a network of additional veins, in distal part of wing veins parallel to posterior margin; large flies (10-15 mm long) with a long beak; larvae parasitic in Coleoptera, Orthoptera and Hymenoptera .......... Nemestrinidae <Habits>; <Adults> & <Juveniles>
10 (9). Only 2 pulvilli on tarsi under claws; seldom pulvilli totally absent
11 (14). R with 4 branches, R-4+5 in distal half forked
12 (13). Three or four posterior veins present, R-5 meeting wing margin posterior to its apex; flies usually densely setose, often with long beak; wings often more or less darkened; larvae predaceous in egg sacs of locusts, parasitic in larvae and pupae of Lepidoptera, in nests of solitary bees or as secondary parasitoids on larvae of Ichneumonidae, Tachinidae, etc. ......... Bombyliidae <Habits>; <Adults> & <Juveniles>
13 (12). Five posterior cells present; frons and vertex situated in impression between eyes; larvae or middle-sized flies, usually with an elongated cylindrical abdomen; adult flies predators of different insects; predaceous larvae live in soil or rotting wood; some (Laphria) in holes of larvae of longicorn beetles ........... Asilidae <Habits>; <Adults> & <Juveniles>
14 (11). R with 3 branches, R-4 and R-5 fused, forking absent
15 (16). Additional longitudinal vein present between R-4+5 and M, which crosses medial transverse vein; posterior cell 1 closed . Middle-sized flies, often with yellow stripes or spots on abdomen; larvae with posterior spiracles closely set on apex of tube; larvae predaceous in some genera, mainly in colonies of aphids, including root aphids, but also predatory on eggs of leaf beetles, younger instar or gregarious larvae of Lepidoptera, psillid nymphs, etc. ............ Syrphidae <Habits>; <Adults> & <Juveniles>
16 (15). Additional longitudinal vein between R-4+5 and M, which crosses medial transverse vein absent; posterior cell 1 open; small flies with a characteristic head, entire surface of which is occupied by huge eyes; larvae parasitic in leafhoppers ......... Pipunculidae <Habits>; <Adults> & <Juveniles>
17 (8). Anal cell closed and always short, usually obtuse and arched convex distally, sometimes absent
18 (21). Arched suture and lunule above antennae not developed
19 (20). Transverse vein rm at a considerable distance from wing's base; R often with 4 branches, M with 2-3 branches; anal and discal cells usually not fused; anal cell of a considerable or moderate size, or lacking; dusky, middle-sized or small flies with a characteristic beak extended downwards; adult flies and other larvae usually predators .......... Empididae <Habits>; <Adults> & <Juveniles>
20 (19). Transverse vein rm close to wing's base; R always with 3 branches, M usually with 1 branch; anal and disal cells always fused; anal cell small, seldom lacking; small or middle-sized flies, often green, metallic; adult flies predaceous, larvae usually also predatory, live in soil, some (Medetera) under bark .......... Dolichopodidae <Habits>; <Adults> & <Juveniles>
21 (18). Arched suture and lunula above antennae clearly developed
22 (23). Arista on antennal segment 3 absent; segment 3 large, reaching lower margin of face; larvae parasitic in mealybugs of subfamily Monophlebinae, some species introduced into North America to control Icerya purchasi ........... Cryptochaetidae (Cryptochaetum iceryae.)
24 (25). Costal vein without break; Sc developed before fusing with C; small flies (2-4 mm long), gray, often with black spots on abdomen; larvae predaceous in colonies of aphids or on mealybugs ............ Chamaemyiidae <Habits>; <Adults> & <Juveniles>
25 (24). Costal vein with break; Sc reduced apically and not reaching C .
26 (27). Anal vein and anal cell absent; head without large setae; only genus Thaumatomyia has important entomophagous species; small flies with yellow body, thorax with black or reddish stripes, scutellum flat with apical setae close to each other; larvae predatory on root aphids ........... Chloropidae <Habits>; <Adults> & <Juveniles>
27 (26). Anal vein and anal cell present; two orbital setae directed backward; in front of them, two frontal setae at anterior frontal margin viewed inside; dusky setae diverging; ovipositor soft, telescopic; wings with dark spots on transverse veins; larvae of Tuaranodina coccidarum Stakelberg predatory on Comstock mealybug, some species of Odinia parasitic in beetles .......... Odiniidae
28 (1). Antennae with multiple segments, and not less than 6 segments; segments, excluding two basal ones, similar to each other .......... Nematocera [Important entomophagous species present only in one family].
29. Costal cell goes around the whole wing; not more than 6 longitudinal veins present; transvere veins absent; ocelli absent; small flies; larvae mostly orange or reddish, with a characteristic lobe on ventral side of thoracic segments; larvae of some species predatory on aphids, mealybugs, psillid nymphs or spider mites ......... Cecidomyiidae <Habits>; <Adults> & <Juveniles>
Trjapitzin, V. A. 1982. A key for identification of families of parasitic and predatory Diptera, p. 249-54. In: V. A.
Trjapitzin, V. A. Shapiro & V. A. Scheptilnikova (eds.), Parasites and Predators of Agricultural Crop Pests, 2nd ed. Kolos Publ., Leningrad. 256 p.