Flies

Order Hymenoptera

The Flies (Order Hymenoptera) includes 5,194 species across 102 families and 1,491 genera in our directory.

About Flies

Hymenoptera includes over 150,000 described species of ants, bees, wasps, and sawflies. Earth harbors approximately 20 quadrillion (20×10^15) ants, with a combined biomass of ~12 megatons of dry carbon - exceeding the combined biomass of all wild birds and mammals (PNAS, 2022).

Economic Impact

Pollinators contribute $235-577 billion worth of annual global food production (FAO). In the U.S., bee pollination alone benefits crops valued at $18 billion annually, and honey bees are responsible for $5.4 billion in agricultural productivity. Between April 2023-2024, 55.1% of managed honey bee colonies were lost. The U.S. bee population dropped from 5 million to 2.5 million.

Ecological Role

About 35% of the world's food crops depend on animal pollinators. The chocolate industry, valued at over $100 billion, depends on pollinating flies and midges. Ants are the dominant soil engineers in most terrestrial ecosystems, turning more soil than earthworms in many habitats.

Families in Hymenoptera (102)

Species in Hymenoptera (5,194)

Woolly Catkin Gall Wasp

Callirhytis quercusoperator

Cynipidae

Produces galls on flowers in the red oak group: "Oval masses 2 to 3 inches in diameter, hairs greenish white or rose tinted, sometimes deep red, there may be 150 or more cells each less than 1/10 of an inch in diameter."

Wooly Pavement Ant

Tetramorium lanuginosum

Formicidae

Identification: Very hairy and round myrmicine ants with long propodeal spines and obvious antennal scrobes.

Wroughtonia ferruginea

Braconidae

Identification: Body entirely ferruginous, antennae dark with white annulus, hind tibiae with "tips" dark.

Xanthoteras radicola

Cynipidae

"Found at the base of Q. alba that was heavily infested with T. quercusforticorne, starting to rot which is consistent with the literature ... the galls that I found were seemingly slightly underground. There was a bit of leaf litter and other debris

Xenoglossa strenua

Apidae

member of the subgenus Eoxenoglossa (2 spp., both restricted to the US & n. Mexico)

Xenoglossodes wilmattae

Apidae

Type Locality: Port Isabel, Cameron Co., Texas (Cockerell, 1917)

Xeralictus biscuspidariae

Halictidae

Males are fooled into visiting flowers of Mohavea confertiflora , which offer no nectar reward but mimic flowers of the females pollen hosts in the genus Mentzelia (e.g. M. involucrata ). The Mohavea flowers even have a dark spot at the center of the

Xestophanes brevitarsis

Cynipidae

Xestophanes brevitarsis is a gall wasp that causes galls to form on Tormentil ( Potentilla erecta ) and Trailing Tormentil ( Potentilla anglica ). The galls are seen more often than the adult. Galls are usually found on the aerial stem or sometimes a

Xestophanes potentillae

Cynipidae

The larvae of the gall wasp Xestophanes potentillae causes galls on the stem or petioles of Creeping Cinquefoil (Potentillia reptans) . The galls can be found very low down close to, or below soil level. Several galls can often been seen on the same

Xiphydria maculata

Xiphydriidae

Identification: Females are readily identifiable by the combination of white antennae (only shared with X. polia ) and reddish-orange legs.

Xiphydria mellipes

Xiphydriidae

Identification: Per Spencer Monckton here , species of Xiphydria "are easily identified by colouration: black antennae, red legs, and black abdomen with lateral white spots says ... Xiphydria mellipes." This species prefers birch. Larvae bore and fee

Xiphydria polia

Xiphydriidae

Identification: Females are readily identifiable by the combination of white antennae (only shared with X. maculata ) and entirely black legs. Males are unique in their white antennae.

Xiphydria tibialis

Xiphydriidae

Identification: Females have black antennae, black and white-marked legs, and the abdomen usually black (occasionally red) with white to yellow spots. Males are recognized by the mostly yellow mesopleuron and the black ground color of the head. Addit

Xorides humeralis

Ichneumonidae

Identification: Temple area with extensive striae, central lobe of mesoscutum with a broad median longitudinal groove, and the second trochanter of the foreleg with a small pre-apical spine. (Porter, 2005) The latter character is unique to this speci

Xorides stigmapterus

Ichneumonidae

head and thorax mostly black in specimens from the north, red in material from se.US (MD‒FL along the Coastal Plain) ‘X. stigmapterus’ may be a species complex

Xyela bakeri

Xyelidae

Identification: Females with ventral margin of the saw-like end of the abdomen straight, the sheath distinctly short and stout with the dorsal and ventral margins parallel until the dorsal sharply extends down to meet the ventral margin towards the e

Xyela linsleyi

Xyelidae

Identification: Females with ventral margin of the saw-like end of the abdomen shallowly curving down, the sheath shorter than 6.5 mm, without the dorsal and ventral margins abruptly meeting at the end to form an acute apex, and in cross section ovul

Xyela middlekauffi

Xyelidae

Identification: Females with ventral margin of the saw-like end of the abdomen straight, the sheath with the dorsal and ventral margins tapering throughout their entire length to an acute apex, the cross section of this sheath diamond-shaped, less th

Xyela minor

Xyelidae

Xylocopa griswoldi

Apidae

Identification: Can be identified with reference to wing color, shape of the scutellum, and distribution Confounded in many publications with X. mexicanorum

Yelicones pilops

Braconidae

Identification: Wings uniformly but lightly infuscated with dark veins, body with complex pattern of dark brown and ivory

Yellow Meadow Ant

Lasius flavus

Formicidae

The Yellow Meadow Ant is, as the name suggests, yellowish brown in colour. A number of features distinguish it from other similar species of ant, including the fact that the lower sections of the antennae and the tibiae lack hairs. The workers are ar

Yellow-banded Bumble Bee

Bombus terricola

Apidae

Identification: see discoverlife.org for detailed descriptions of queen and male; worker resembles queen in general, but pubescence relatively longer **Listed as Vulnerable by the IUCN Red List of Threatened Species ** Declines of this species were f

Yellow-fronted Bumble Bee

Bombus flavifrons

Apidae

Identification: The typical form is very similar to B. centralis in that a yellow T1-T2 contrast with a red T3-T4, but flavifrons has a longer malar space and black hairs intermixed on the scutum anterior to the black interalar band.

Yellow-headed Spruce Sawfly

Euura alaskensis

Tenthredinidae

serious pest of spruce trees; damages nursery crops and urban trees

Yellow-horned Horntail Wasp

Urocerus flavicornis

Siricidae

Identification: Females have the 1st, 6th, and part of the 7th abdominal segments yellow. Males have the 2nd - 5th orange-yellow.

Yellow-legged Mining Bee

Andrena flavipes

Andrenidae

The males look different to the females. They are slimmer, covered in sparser hair and lack the dense brush of orange-yellow hairs on the hind leg. Nests in exposed banks and cliffs, tended lawns, flower beds, roadside verges and in sparsely vegetate

Zacosmia maculata

Apidae

Identification: Diagnostic characters include: fusiform (tapered at both ends, with median segments thickened) male flagellum; the marginal cell is ~ half as long as the distance from cell apex to wing tip. Cleptoparasite of Anthophora (Heliophila) ,

Zagryphus nasutus

Ichneumonidae

Zagryphus nasutus (Zagryphus nasutus) is a species in the family Ichneumonidae, commonly known as ichneumonid wasps, belonging to the order Hymenoptera (Ants, Bees, Wasps and Sawflies). It is classified within the subfamily Tryphoninae, tribe Oedemop

Zaischnopsis bouceki

Eupelmidae

Identification: "Dr. Gibson described in his synopsis of this genus females having the axillae and scutellum bicolored, and with a yellow ovipositor." [see Ross Hill's comment here ]

Zapatella quercusphellos

Cynipidae

Causes stem swellings (galls) on Quercus ilicifolia, Q. imbricaria, Q. falcata, Q. cinerea, and Q. myrtifolia , containing 1-4 cells; club-shaped when terminal. Green and fleshy in May, becoming woody later.

Zatypota anomala

Ichneumonidae

Identification: Scutum dark brown with yellow stripes along notauli; flagellum with 16 segments in female, 14 in male; T3 0.55 length-to-width

Zele deceptor

Braconidae

The head and abdomen of this insect are orangey red and the wing has a yellowish stigma. Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID met

Zethus miscogaster

Vespidae

Identification: Stem of second segment of metasoma longer than that of first

Zimmermann's Mud-dauber Wasp

Chalybion zimmermanni

Sphecidae

Identification: Males differ from californicum in part by having long white thorax and head pubescence and lighter wings. Separation of females is based on the morphology of the pleuron, which is usually impossible to do from images. 2 subspecies in

Zopheroteras compressum

Cynipidae

On red oak ( Quercus rubra ), produces a white, subglobular gall on the undersides of leaves in fall, just as the leaves are turning. The type gall is 2.7 by 1.8 by 1.8 mm, tan, and slightly wrinkled.

Zopheroteras guttatum

Cynipidae

Causes spherical, 1.45-2.5 mm galls, with purple spots, single on a secondary vein on underside of Quercus palustris, imbricaria , or texana leaf, in fall. The images placed in this section show upperside galls on Q. phellos and rubra . These species

Zopheroteras sphaerula

Cynipidae

Larvae develop in galls on leaves of red oak ( Quercus rubra ): "Nearly spherical, greenish or tinged with red, on upper or lower side of leaf, single or 3-4 in a row, dropping in Oct. Adults emerged Mar. 13 and Apr. 6 the next spring."

formerly Lasius flavus

Lasius brevicornis

Formicidae

At the beginning of the colony there are several queens which groom each other and prevent fungal infections that might kill solitary queens. But when the first workers eclose and start foraging, the extra queens are eliminated; mature colonies gene

formerly Leptothorax muscorum

Leptothorax canadensis

Formicidae

Common but inconspicuous. It is essentially boreal and montane in distribution. Ellison et al. recognize 2 unnamed spp. from NewEngland: -AF-can is a large black species with short (less than 0.04 mm) erect hairs on the mesosoma and no subpostpetiola