mesothorax

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mesothorax

[¦me·zō′thȯ‚raks]
(invertebrate zoology)
The middle of three somites composing the thorax in insects.
References in periodicals archive ?
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.
2 black npl (the only black setae on mesonotum, other macrosetae weakly developed), general setae longish white.
Pronotum: Distinctly wider than long, lateral margins with a vertical projection, separated from mesonotum by a deep suture.
PMG: depth of promesonotal groove; measured by establishing a line tangent to dorsalmost convexities of pronotum and mesonotum, measuring perpendicular distance from this line to bottom of promesonotal groove.
Adults can be easily distinguished by the characteristic marks on mesonotum and abdomen (Couri and Carvalho, 2002: 166, figs 33 and 34; Marques and Couri, 2007:438, figures 1-21); holoptic males; arista with long plumae; dorsocentral setae 2:4; katepisternals 1:1 and sternite 1 setulose.
Pronotum elongate, moderately compressed anteriorly, extending onto lateral surfaces, ending in proximity to single well developed rectangular prosternal plate, covering almost the entire venter; meso- and metanotum less than half the length of the pronotum, thoracic nota with minute hair-like sensilla; spiracles in plural regions proximal to anterolateral margins of the mesonotum.
Color Body pale dull yellowish (possibly greenish in life; Muir 1931) with reddish mid-dorsal red to brown stripe following median carinae of coryphe and pronotum, weaker on midline mesonotum and commissural margin of forewings.
52 (entire [male]), figs 223, 224 head, 225 antenna, 226-227 [male] terminalia, 228 [female] terminalia; Hull 1962: 212; Oldroyd 1970: 295 (key); 1980: 371 (catalogue); Geller-Grimm & Hradsky 2003: 174 (figs 6 & 14 mesonotum, 22 & 30 abdominal terga).
Mesonotum without well defined golden lines, abdominal sternite 3rd, 4th segments with apically black band and palpi of female one third length of proboscis.
Thorax: Mesonotum red chestnut, with white tomentum and defined longitudinal testaceous bands; pleura and humeral callus orange with fine white tomentum; anterior and posterior spiracles pale yellow; legs with coxae, trochantes and femora orange, mid and posterior femora with apexes dark chestnut; mid femur with three apical posterodorsal setae and one antero-medial setae.
Measurements (mm): Bodylength 79, head 5, antennae 65, pronoturn 5, mesonotum 10, metanotum 5, median segment 7, profemora 21, mesofemora 14, metafemora 23, protibiae 22.