Eupithecia is the largest genus of moths of the family Geometridae, and the namesake and type genus of tribe Eupitheciini. Species in the genus are, like those of other genera in the tribe, commonly known as pugs. The genus is highly speciose, with over 1400 species, and members of the genus are present in most of the world with exception of Australasia. Roughly a quarter of described Eupithecia species occur in the Neotropical realm, where they have an especially high species diversity in the montane rain forests of the Andes. The genus includes a few agricultural pest species, such as the currant pug moth, Eupithecia assimilata, which is a pest on hops, and the cloaked pug moth, Eupithecia abietaria, which is a cone pest in spruce seed orchards.

Adult specimens of Eupithecia are typically small, often between 12 and 35 mm, with muted colours, and display a large amount of uniformity between species. As a result, identification of a specimen as part of genus Eupithecia is generally easy, but identifying the exact species is difficult and often reliant on examination of the dissected genitals. Most species share a characteristic resting pose in which the forewings are held flat at a right angle to the body—that is, the costal margins of both forewings form a more-or-less horizontal line—while the hindwings are largely covered by the forewings. They are generally nocturnal.

Of the species where the larval behaviour is known, most feed from the flowers and seeds of their food plants rather than the foliage. Many species have a very specific food plant. The larvae of all but one of the endemic species of Eupithecia from Hawaii are ambush predators of a wide variety of insects and spiders. These ambush predators have raptorial legs, with which they grab prey that comes into contact with their hind end.

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