prothorax

(redirected from Pronotum)
Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to Pronotum: pronotal, Propleuron

prothorax

[prō′thȯr‚aks]
(invertebrate zoology)
The first thoracic segment of an insect; bears the first pair of legs.
References in periodicals archive ?
Pronotum with metazona elevated and expanded slightly sideways, lateral lobe subpentagonal, humeral sinus concave but not as developed (Fig.
DESCRIPTION: Male: COLORATION: ground color including antennal segments I to III pale brown; antennal segment IV dark reddish brown with apical third paler; rostral segments I to IV reddish brown; anterior half of anterolateral margins of pronotum reddish brown; anterior and posterior lobe of metathoracic peritreme pale yellow; posterior margin of acetabulae, coxae and trochanters reddish brown with brownish orange marks; femora pale brown with reddish brown hispid tubercles; tibiae pale brown with reddish brown marks; tarsi reddish brown with dark brownish orange irregular marks; apical margin of corium ad some veins dark reddish brown; hemelytral membrane translucent, veins brown.
2 (5) Dorsal surface of pronotum glabrous or with traces of extremely fine microsetae (readily obvious under 100x magnification).
Piceous; clypeal margins and pronotum sides paler; legs reddish-brown; antennal club rufo-testaceous.
Disc of pronotum flatter and less tectate; lateral carinae of pronotum curved slightly outwards at midlength, rather than being straight.
1B): Ovoid body with the maximum width at the second abdominal segment level; light browned head, jugum and tylus; four dark browned spines at the margin of the jugum; reddish small eyes; dark browned thorax; pronotum with disperse punctuations at its surface; mesonotum with a transversal punctuation row at the middle part; metanotum with a transversal dark browned row of punctuations at its base; pale yellowed antennal and rostral segments; convex mesonotum at the posterior margin in the middle part indicating the scutellum formation; yellowish to white legs; pale pinked abdomen.
With regard to the widening of the tegmen and the course of its veins, Eulophophyllum seems to be most closely related to the genus Leptoderes Serville, 1838 [distributed in tropical SE Asia; see OSF (2016)] although in the latter genus the tegmina are widening towards the apex, and the head and pronotum are different.
Pronotum quadrangular, glabrous, with anterior angles slightly acute and sides with scarce punctures close to lateral fossae; marginal groove narrow on anterior margin, occupying 1/3 of pronotum anterior border.
Or there might be some variations as a result of interactions with the environment in their morphological structures such as head (where equally important structures are located like mandible, eyes and antennae), pronotum (which serves primarily as the attachment of muscles for locomotion of the front legs and at the same time for protection of the pterothoracic segments) and elytra (which is very important not only for protection of the inner wings and body but also in balance for flight and control in swerving in looking for another host tree), hence a good characters for study.
Pronotum elongated, sigmoid in lateral view; supracoxal expansions decided, acute, sub-foliaceus; dorsal surface bearing in the collar a medial and postmedial paired tubercle, or a single low swelling shaft with a pair of tubercles mesad at the caudal margin.