Peritreme

Per´i`treme


n.1.(Zool.) That part of the integument of an insect which surrounds the spiracles.
References in periodicals archive ?
1B) with small ovate aperture, peritreme well-developed, sword-shaped with apex subacute and facing upward, evaporatoria large and very well-defined; membrane of hemelytra equal to abdomen.
Incomplete peritreme was visible at the anterior and dorsal parts of the spiracles.
Posterior spiracles do not show ecdysial scar, peritreme is incomplete with a pair of oval spiracular openings (Fig.
Ventral surface: Pale brown, ostiolar peritreme creamy white, abdominal venter bearing short, recumbent, pale, simple setae, these setae longer and more numerous on lateral margins of genital cavity.
Spiracle I elongate, with fine peritreme and covered by wing thecae; spiracles II-IV ovate, prominent, with strongly selerotized peritreme; spiracle V-VIII closed.
The pupae had prominent annular respiratory stigmata II, III, and IV, with pigmented and truncated peritreme, notorious atrophied abdominal respiratory stigmata VIII, but as high as wide, and equally pigmented dioneiform V and VI structures.
The Pseudophloeinae can be distinguished from other Coreidae subfamilies by having the tibiae terate, without a dorsal sulcus; lack of a median dorsal impression on the head; enlarged posterior abdominal angles of the seventh segment; eighth female paratergite without a functional spiracle; particular genitalic characters; and by the structure of the scent-gland auricle, in which the peritreme has a dorsal ridge entire or shortly bilobed, not with a I'-shape (Dolling 1977, 1978, 1986).
2A) ovate, obliquely placed with well-developed sword-shaped peritreme with anterior margin a little concave, evaporatoria very well-defined; membrane of hemelytra almost equal to tip of abdomen.
15); dorsal abdominal scent glands on abdominal segments 4-5 and 5-6 with rounded ostioles, bearing closing cuticular valve, ostiolar peritreme spout shaped (Fig.
Macropterous form: Thorax: Pronotum wider than long, with hispid tubercles, subquadrate, flattened, not declivous; frontal angles rounded, not projecting; humeral angles obtuse, not exposed; collar indistinctly depressed, not separated by a distinct incised line; middle third of pronotal disk with a broad longitudinal sulcus; anterolateral margins obliquely straight, roughly granulate; posterior margin concavely arcuate before base of scutellum; prosternum depressed; meso and metasternum sulcate; anterior lobe of metathoracic peritreme weakly reniform, posterior lobe subacute, raised; evaporative area short; posterior margin of metapleura with outer third obtusely rounded, and slightly raised.
Within the Euseiini, this genus is diagnosed on the basis of different characters, including the reduced, vase shaped or ovoid female ventrianal shield; peritreme usually short, not reaching to level of setae j3; chelicera reduced, with small teeth on fixed digit clustered apically and with inner margin strongly concave, and movable digit with one or no tooth.