Thynnid flower wasp

Conservation Status

IUCN Red List

not listed

NatureServe

not listed

Minnesota

not listed

Description

Myzinum carolinianum is a common, medium-sized, parasitoid wasp. It occurs in the United States from New York State to Florida, west to Minnesota and eastern Texas, and in southern Ontario and Quebec Canada. It is uncommon in Minnesota.

Adults are active from June to September. Little information about the biology of Myzinum carolinianum can be found. Adults in the genus Myzinum are found in a wide range of habitats, including meadows, fields, and lawns. They feed on pollen and nectar from the flowers of at least 22 species of plants, mostly in the Asteraceae and Apiaceae families. The larvae are external parasites on the larvae of beetles, mostly scarabs (family Scarabaeidae) and especially May beetles (Phyllophaga spp.), but also tiger beetles (family Cicindelidae).

Females are 9⁄16″ to 11⁄16″ (14 to 18 mm) in length. The body is short and broad compared to the male. It is somewhat hairy and mostly black with yellow areas and yellow markings. The front part of the body (mesosoma) is connected to the rear part (metasoma) by a narrow waist. The amount of yellow is highly variable.

The compound eyes are notched to slightly indented on the inner margin, and there is a yellow band along the inner and rear eye margins. There is a prominent, yellow, raised, transverse facial ridge (antennal lobe) where the antennae attach. The antennae are thread-like and black, and they have 12 segments. They are usually held straight, not coiled. There are yellow markings on the first antennal segment (scape). The plate on the face (clypeus) bulges prominently forward. It is partially yellow and is rounded on the lower margin. The bases of the jaws (mandibles) are yellow.

The thorax is longer than wide and it has three segments, from front to back the prothorax, mesothorax, and metathorax. The upper plate on the prothorax (pronotum) is large and robust. It is black with a conspicuous, broad, transverse band spanning the middle or rear margin and reaching near the lateral edges.

On the mesothorax, the large front plate (scutum) is entirely black. The rear plate (scutellum) has a single arcuate yellow band across the middle. The plate on each side of the second segment (mesopleuron) has a yellow spot on the top front corner. The tegulae are yellow.

The surface of the metasoma is covered with silvery hairs except for the last segment, which is shiny. The upper plate (tergum) of each of the first four metasomal segments (T1 to T4) has a broad yellow band on each side. On the underside, the sterna of segments 2 and 3 each have a lateral yellow spot, and the last sternum is rounded at the tip.

The forewings are strongly bicolored—mostly tinted light brown, but with dark brown tinting along the leading edge (costal margin).

The legs are variable in color, black with little to extensive yellow and reddish markings.

Males are ⅝″ to ¾″ (15 to 19 mm) in length. The body is long and slender. The antennae are black, they have 13 segments, and there is a small yellow spot on the upper side of the scape. The clypeus is entirely yellow. The pronotum has a narrow yellow band on the front, broken in the middle, and a broad, unbroken band at the rear margin. The scutum has a large spot in the middle, the scutellum has a broad band in the middle, and the metanotum has a slightly smaller band in the middle. The mesopleuron has a large yellow spot at the front and another at the rear. The metasoma is narrower, cylindrical, the yellow bands are narrower, and the last segment has two teeth/lobes flanking a central, upwardly curved, false stinger. The wings are mostly clear with dark tinting toward the tip. The costal margin and the stigma are distinctly orange, contrasting sharply with the dark brown interior veins.

Size

Female Total length: 9⁄16″ to 11⁄16″ (14 to 18 mm)

Male Total length: ⅝″ to ¾″ (15 to 19 mm)

Similar Species

Habitat

A wide range of habitats, including meadows, fields, and lawns

Ecology

Season

June to September

Behavior

Life Cycle

Larva Food/Hosts

Larva of beetles, mostly in the families Scarabaeidae and Cicindelidae

Adult Food

Pollen and nectar of mostly Asteraceae and Apiaceae plants.

Distribution

Sources

24, 27, 30, 82.

Myzinum carolinianum (Panzer) Panzer in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-08-26 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgyy9

Kimsey, Lynn S., 2009, Taxonomic purgatory: Sorting out the wasp genus Myzinum Latreille in North America (Hymenoptera, Tiphiidae, Myzininae). Zootaxa 2224: 30–50.