apical angle


Also found in: Dictionary, Encyclopedia.

ap·i·cal an·gle

the angle between two plane surfaces of a prism.
References in periodicals archive ?
the apical margin of the protibia of the female has a subcarinate ridge ending in an elongate, subacute uncus projecting posteriad, and has an acute mucro on the inner apical angle, partly concealed by 2 clusters of coarse setal brushes anterior and posterior to the mucro.
ii) The shell dissymmetry D is strongly increasing with the growth-dissymmetry index [delta], less intuitively decreasing with the apical angle [alpha] and strictly independent of the differential-growth index [rho] and independent of the differential-growth index [rho].
Forewing light yellow, costal margin tinged slightly with grey, pagina with some irregular brown transverse lines, strongest one from inner side of apical angle to middle of posterior margin, dark brown oblique line starting below apical angle to metagonia, apical angle slightly round, outer margin curved, fringe scales grayish-yellow.
9) (Pseudavakubia) 10 2 Shell with distinctly acuminate apex and tapering spire (apical angle generally < 120[degrees], spire angle <60[degrees]) 3 -- Shell apex more rounded, spire aspect less tapering (apical angle at least 120[degrees], spire angle >62[degrees]) 4 3 Adult shell >5 mm, elongate, apex strongly acuminate, spire appearance less tapering; apical angle <100[degrees].
Small shell of 10 to 11 whorls with gradually tapering spire; whorls evenly rounded; sutures impressed; one fine, spiral thread just below suture and one fine thread just above suture; three larger, evenly spaced threads on central portion of whorl; interspaces wider than threads; apical angle of 26 degrees; aperture and slit not observed.
The species name is derived from the Latin words "rotundatus", referring to the forewing with a black round spot at the apical angle.
Marginal impression shallow, narrow near apical angle, broadly widened to basal angles.
Parameres short, dorsocaudally directed, twice wider at basal half, narrower and subparallel sided at the apical half; in caudal view, apical half with profile rectangular with acute inner apical angle (Fig.
Genae mostly dark brown but apical small part yellow; in posterior view, process of anal segment of male relatively long and stout, sinuous, situated on left side of ventral margin; outer apical angle of genital styles forked 4
Head dark brownish orange, with 2 black maculae on posterior third of interocular space; tylus pale orange; most of juga and margin near eyes cover with a whitish cerumen; antennal segment I pale orange, segments II and III bright yellow with base and apex slightly darker, segment IV dark brown or reddish brown with base yellow; anterior lobe of pronotum dark brownish orange, posterior lobe yellowish orange with punctures slightly darker; scutellum with basal third yellowish orange and the rest reddish brown; clavus ochraceus with brownish orange punctures; corium hyaline, with punctures, a macula situated near middle third of endocorium, and a rectangular macula situated in the apical angle pale orange in color; membrane ambar.
Forewings with acute apical angle, outer margin approximately straight, oblique, posterior margin sinuate, with irregular markings at apical half (Figs.