There were about 410 described species of Nabidae, or damsel bugs, known by the year 2011. They range in all regions of the world, but they are very abundant in the tropics. Diagnostic characters of these "damsel bugs" are the membrane of the hemielytron that has several small cells around its margin. They have enlarged, raptorial front femora. They are slender in body and ocelli are present; the rostrum 4-segmented; antennae 4-, rarely 5-segmented.
Probably all are predators as nymphs and adults on various stages and groups of phytophagous insects, e.g., aphids, lepidopterous eggs and young larvae, leafhoppers. They may be commonly found on low herbaceous vegetation, shrubs and grasses. They may be beneficial in naturally occurring control. Species in the genus Nabis are very common and abundant in fields of legumes such as alfalfa, but they can occur in many other crops and in non-cultivated areas. They are yellowish in color and have large, bulbous eyes and stiltlike legs. They are generalist predators, catching almost any insect smaller than themselves, including members of their own species. They are soft-bodied, elongated, winged terrestrial predators. Many species grasp onto their prey with their forelegs, quite like the preying mantids, and the proboscis is inserted through a cut.
Nabidae are beneficial because of their predation on many types of agricultural pests, such as lepidopterous larvae, aphids, and lygus bugs.Nabis ferus L., a natural enemy of potato psyllid, the meadow plant bug and sugar beet leafhopper in North America, feeds on the larvae of Ascia rapae L. in Europe. Larger caterpillars are attacked only at the time of the molt. Complete paralysis quickly follows the penetration of the beak into the prey, and death occurs within 24 hrs. even without feeding. A key references is Mundinger (1922).
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Blatchley, W. S. 1926. Heteroptera or True Bugs of Eastern North America, with Special Reference to the Fauna of Indiana and Florida. Nature Publ. Co., Indianapolis, Ind. 1116 p.
China, W. E. & N. C. E. Miller. 1959. Checklist and keys to the families and subfamilies of the Hemiptera-Heteroptera. Bull. British Mus. Nat. Hist. Ent. 8(1): 1-45.
Miller, N. C. E. 1971. The Biology f the Heteroptera. E. W. Classey Ltd., Hampton Middlesex, England. 206 p.