FNZ 25 - Cercopidae (Insecta: Homoptera) - Morphology
Hamilton, KGA; Morales, CF 1992. Cercopidae (Insecta: Homoptera). Fauna of New Zealand 25, 40 pages.
( ISSN 0111-5383 (print), ; no. 25. ISBN 0-477-02636-2 (print), ). Published 25 May 1992
An elementary knowledge of the structure of adult spittlebugs (Fig. 1, 2) is necessary for identification of species. More detailed accounts of spittlebug morphology can be found in Doering (1922), Snodgrass (1935), and Hamilton (1982).
Spittlebugs, like most insects, have three distinct body sections: head, thorax, and abdomen. The connections between the sections are narrow and the body form is greatly compacted, obscuring these divisions. The sections of the body are most clearly visible from below.
The more or less conical head has an upper part (the crown) and a lower part (the face) visible from directly above and directly below respectively. These are usually separated by a distinct angle, the margin of the crown. The large compound eyes occupy the entire sides of the head. Between them the head is dominated by the frons, which is the greatly inflated outer surface of the sucking pump. This occupies most of the face and extends on to the crown, forming a broadly oval or bean-shaped area just in front of the ocelli, or simple eyes. The antennae are inserted just below the margin of the crown in front of the compound eyes. The mouth with its projecting beak extends backwards between the bases of the front legs.
The boxlike thorax bears the three pairs of legs and two pairs of wings. The two visible parts bchind the head are a shieldlike extension of the first thoracic segment, the pronotum, and the folded forewings. Between these is exposed a small triangular part of the second thoracic segment, known as the scutellum.
The front two pairs of legs are similar to each other. The hind legs are somewhat longer and stouter, and bear prominent spines on the sides and near the tips. Each leg is divided into seven articulated joints. The line separating the first two is often difficult to distinguish. These first two joints (coxa and trochanter) are short compared to the rest of the leg; they make up the leg base. The first long joint beyond these is the femur, the second is the tibia. The three terminal joints form the foot, or tarsus, which is tipped with a pair of claws and a central adhesive pad.
The wings are thin and nearly flat, with thickened struts (the veins) giving structural strength. The forewings are thicker, heavier, and darker than the transparent and membranous hind wings. Only the latter are used in flight, the forewings acting mainly as a protective cover when the insect is at rest.
The globular or tapered abdomen, concave below, is composed of telescoping segments, and the only appendages it bears are the genitalia.
Adult females are readily distinguished by their long, slender ovipositor, which may be up to half as long as the abdomen.
Adult males have a short pair of blunt or tapered processes, the subgenital plates, which serve to protect the copulatory apparatus (Fig. 4). These arise from the ventral margin of pygofers that form the side walls of the genital capsule (Fig. 6). The genital capsule encloses a pair of hooklike styles flanking the penis. The penis is divided into a globular phallobase and a distal, tubular or leaflike aedeagus, which in turn may be composed of a sclerotised theca ending in a membranous, often extensile vesica surrounding the gonopore. Above the aedeagus the slender terminal segments of the abdomen form an anal tube.