Diabrotica longicornis (Say)

Species name

Diabrotica longicornis Say 1823: 460 as Galleruca

Type locality

Arkansa, near the Rocky Mountains.
Colorado, Avondale, Pueblo County [neotype]

Type depository

Type has been lost.
MCZ, neotype, male, verified.

Diagnosis

Body length 4.6-5.2 mm. Body width 2.0-2.3 mm. Head basic color black. Antennae filiformfiliform:
slender antennae with antennomeres of similar shape
, bi- or tricolored, antennomeres 1-3 yellow, upper sides darkened, antennomeres 4-11 brussels brown. Maxillary palpi black or amber brown, labrumlabrum:
the "upper lip" of beetles, a movable sclerite joined under clypeus
black or chestnut. Pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
yellow or sulphur yellow, quadrate, deeply bifoveate, not shagreened. Scutellumscutellum:
small, usually triangular shield between the bases of elytra
piceous or black. Elytra green, yellow or rufous, vittatevittate:
(here) marked by longitudinally extended maculae different from the basic color of elytron
, with one sutural and one humeral chestnut vittae (sometimes reduced to a variable extent). Elytral epipleura completely yellow, elytra surface with four distinct sinuatesinuate:
curved in some way
sulci, strongest behind the humeral callushumeral callus:
<em>(pl. calli)</em> more or less marked tubercle or knob on the anterobasal angle of elytron
and extending beyond the middle. Sutural anglesutural angle:
the posterior angle or apex of the elytron near the suture
of elytra round, punctation scattered, coarse. Abdomen yellow. Tarsi black or amber brown, tibiae black or piceous. Femora uniformly yellow. Aedeagusaedeagus:
the main sclerotized part of the male genitalia; "aedeagus" is used here instead of "median lobe of aedeagus"
symmetric, with four internal sac scleritessclerites:
(here) the sclerotized hooks, spines or plates in the internal sac
.

Known distribution

Mexico, USA: AZ, CO, KS, NE, NM, OK, TX, WY (Krysan & Smith, 1987a)

Host plants

Cucurbitacea, Cucurbita foetidissima Kunth in H.B.K. (Krysan & Smith, 1987a). Zea mays (L.), perennial grasses (Poaceae), Gutierrezia sarothrae (Pursh) N.L. Britt.&Rusby (Clark et al., 2004)

Remarks

Smith and Lawrence (1967) indicated that Say's type series has been lost. In the discussion on this problem they noted that Say's type series of D. longicornis was probably a mixture at least two species: D. virgifera and D. longicornis. Smith and Lawrence indicated that Say's original description is not definitive to separate these two species. In order to preserve two names in the interest of nomenclatorial stability, they proposed the neotype which conforms to Smith and Lawrence's restricted concept of D. longicornis.

Potential problems with identification

Diabrotica longicornis (Say) is similar to D. barberi Smith & Lawrence and D. virgifera LeConte. They can be separated by the following features: in D. barberi the head, tibiatibia:
<em>(pl. tibiae)</em> the forth part of the beetle leg articulated with femur on the one side and with tarsus on the other side
and tarsi are paler than in D. longicornis; in D. longicornis femora are uniformly yellow or green, femora of D. virgifera as a rule are bicolored with dark, chestnut or piceous outer edge. The shape of the internal sac scleritessclerites:
(here) the sclerotized hooks, spines or plates in the internal sac
(especially sclerite 4B) differentiates all three species very well.