Araeoschizus antennatus

Diagnosis
Group III: The limbatus Blaisdell (1943) complex: Femora not toothed. Prothorax with longitudinal groove. Elytral interspaces with squamules

Superficially resembling limbatus Blaisdell; easily differentiated by the long head, more slender prothorax, the very narrow, rounded shoulders, narrow, elongated body. Dark brown ; shiny

Description
Head.- One-fourth longer than broad behind well elevated ocular lobe. Preocular angle evenly, continuously rounded with prominent frontal margin, with two small, well defined annules each side of middle; 2-4 short, sharply inwardly curving bristles. Anterior exterior angle of ocular lobe rounded, seemingly continuation of frontal margin ; rounded , angularly elevated. Sides slightly constricted at eye level ; occipital region broadly angularly rounded. Ocular ridge prominent, highly elevated, gradually shallo­wer behind eyes. Ocular groove shallow :portion anterior to eye shorter. Surface very fi­nely, unevenly granulate-punctate; each impression with a forwardly, slightly recum­bent, short, pale-yellow, club shaped squamule, squamules slightly longer, almost de­cumbent on frons. Posterior margin almost straight, with deep, broad triangular impres­sion on posterior half of well elevated vertex. Margin with erect squamules, which are denser on ocular lobe, more so on ocular ridge. Eyes small, elongate, strongly concave; with 19 facets dorsally , 5 ventrally. -Antennae reaching into posterior fourth of protho­rax. Joints well separated ; 2 longest, broadest, narrower at base; 1 nearly as broad as 2, shorter; 3 broadly rounded at anterior, narrow at posterior end, one-third shorter than 2 ; 4-9 about even (however 4-5 slightly broader); 10 slightly impressed laterally , about as wide as 3; 11 short, about half size of 10. Joints 1-6 with longer erect squamules, from 7 on squamules slightly narrower , shorter ; on 10 hairlike, on 11 more so. Squamules on jo­ints 3-8 on anterior half of each joint; on 9-10 surface uniformly squamulose. Prothorax. - Almost as long as wide on broadest anterior half. Somewhat darker brown than head, elytra; very coarsely granulose. Frontal, posterior margins straight ; la­ter more densely squamulose. Sides broadly rounded behind slightly rounded anterior angle, then gradually constricted towards middle; posterior third nearly parallel, with erect, sparsely spaced pale squamules. Longitudinal groove narrower at middle ; deepest at posterior fourth ; not squamulose. Two longitudinal ridges well elevated, with row of dense, erect, darker yellow squamules; slightly constricted about middle. Surface be­tween ridges, exterior margins of prothorax very densely covered with short, erect squa­mules. Dense, golden -yellow multiple row of squamules on posterior margin, separated in middle, leaning toward ends of two ridges, not forming tufts. Elytra. -About one-fourth longer than head, prothorax combined; slender. Ante­rior margin straight, short, same width as posterior margin of prothorax. Scutellum sharply pointed, well defined. Shoulder narrowly rounded, almost same angle as poste­rior of abdomen ; sides at middle-third almost parallel. Primary cordae prominent, shar­ply elevated with erect, slightly curved club-shaped squamules, somewhat recumbent in posterior fourth. Secondary corda 1 slightly elevated, others not; squamules on secon­dary row, sutural lines sparse; distance between squamules much less than length of squamules; not entire, longest, 4 shortest. Puncture lines prominent, punctures round, deep, with sharp edges; distance between less than half diameter of puncture; surf ace between very finely granulose. Underside. Head. - Surface very coarsely granulose; hour-glass shaped gular groove deep,broad, its margins distinctly squamulose ; surface finely punctulate; basal groove of post gena deep, broad. Mentum slightly broader than long, lighter brown ; densely covered with outwardly projecting, hair-like squamules ; sides, front continuously evenly roun­ded. Terminal joint of maxilla shorter, narrower than proceeding; pale yellowish-brown. Post genal process sharp, prominent, interior base slightly carinate, margin between straight; surface of process, margin of plate evenly densely squamulose; genal area spar­ sely covered with club-shaped, forwardly recumbent pale squamules, which are slightly longer both sides of posterior end of gular impression. Prothorax. -Surface granulose; only area anterior to coxae, prominent prosternal ridge, margin of prosternal process sparsely squamulose. Prosternal ridge slightly eleva­ted, Y-shaped at anterior end ; posterior end sharply constricted, more elevated be­tween coxae; prosternal process broadly rounded, narrowly-pointedly reaching posterior margin of prothorax. . Hindbody. - Surface with large, flat, densely spaced punctures; each punctu re with a narrow, decumbent squamules which is slightly longer than diameter of puncture. Size of punctures for abdominal segment 2 gradually decreases posteriorly; those on seg­ment 5 about one-third of those on 1. Mesosternum short, mesosternal process narrow, slightly broader, flatly rounded posteriorly. Metasternum with narrowly rounded meta­sternal process, which is slightly more elevated than posterior margin on opposite side. Segment 1 with broad, sharply forwardly pointing, triangularly shaped process between posterior coxae, which is blackish-brown, impressed in middle. Segments as above. Legs. - Femorae of uniform thickness; posterior pair longest; middle pair slightly smaller than anterior. Sides sparsely, edges densely covered with short, recumbent, club-shaped pale squamules. Tibiae more squamulose than femora, with distinct tibial collar consisting of row of short, erect, golden-yellow spine-lie squamules. Tarsi densely squamulose throughout. Length : 4.0-4.2 mm.

Distribution
Mexico: Baja California (type) Holotype :Mexico, 10 miles S of Punta Prieta, Baja California Norte, June 21, 1938, Michelbacher and Ross Collectors (CAS). Additional specimens :Mexico, 13 mi. E of El Rosario, Baja California Norte, D. Q. Cavagnaro, G. E. & E. S. Ross, and V. L. Vesterby Collectors, 2 specimens (CAS). Santa Ynez, Baja California Norte, April 11, 1978, H. Clark Collector, 1 specimen (CID).

Specimens from El Rosario and Santa Ynez (some 60 mi. apart ; 120 mi. North of type locality) slightly differ from the holotype. However, insufficient material makes it unjustified to handle those as a subspecies to antennatus.The differences may be summa­rized as follows : Slightly more slender. Head narrower posteriorly. Occipital impression broad, flat. Ocular groove posterior to eye flat, not outlined. Ocular ridge shallow ;with erect longer squamules. Eye large, 18 facets dorsally, 5 ventrally. Antennae very densely covered with semierect long squamules. Surface of head densely punctured with smaller punctures than prothorax. Prothorax similar to antennatus, except squamules on longitudinal median ridges (creating groove), and along margins of prothorax, goldish-yellow, long, erect. Elytral costae with denser row of longer erect squamules. Sutural line very narrow, not grooved, tightly fused, two rows of erect squamules sparsely spaced, short, same size shape as on secondary rows.