Neltumius texanus (Schaeffer)

Romero, Jesus & Johnson, Clarence Dan, 2003, Revision of the Genus NELTUMIUS Bridwell (Coleoptera: Bruchidae), The Coleopterists Bulletin 57 (2), pp. 219-236 : 229-230

Neltumius texanus (Schaeffer)

Bruchus texanus Schaeffer, 1904:231 (Esperanza Ranch, near Brownsville, Texas); Fall 1910:162; Pic 1913:52.

Mylabris texanus: Leng 1920:305 .

Neltumius texanus: Bradley 1947:36 ; Blackwelder and Blackwelder 1948:45; Kingsolver 1964:110; Johnson 1968:1270; Bottimer 1968:1025; Center and Johnson 1976:196; Johnson 1978:432; Johnson and Kingsolver 1981:416; Johnson and Kistler 1987:263; Hetz and Johnson 1988:135; Johnson 1989:761; Udayagiri and Wadhi 1989:95; Johnson 1995:42.

Description. Male. Integument Color. Antennae, head, thorax, abdomen, and tarsi black; femora and tibiae brown with apices black.

Vestiture. Antennae black with white pubescence; frons sparsely covered with white and pale yellow hairs; prothorax white with vaguely defined paired brown spots at apex; scutellum covered with white pubescence; elytral pubescence white and black hairs in contrasting pattern; sides and venter with white hairs in mottled patterns ( Fig. 11); legs clothed with white and pale yellow hairs with median brown band on posterolateral face of each tibia; without tuft of hair on first abdominal sternum. Pygidium evenly convex, whitish-gray in basal third, mixed white and pale yellow with narrow median gray line in apical third.

Head. Antenna with first four segments and the last filiform, segments 5–10 subserrate, frons with median carina glossy black, head finely punctate; labrum bare, somewhat sulcate, yellowish brown at apex; eyes rounded, dark brown; ocular sinus 0.6 to 0.62 width of eye.

Prothorax. Subconical, pleura slightly concave; disk convex with paired brown, obsolete tuberosities near base flanking triangular white antescutellar patch; base strongly lobed at middle, sinuate laterally, posterior corners acute; apex rounded.

Mesothorax and Metathorax. Scutellum small, subquadrate; elytron evenly convex; humerus prominent, granulate, lacking serrate carina connecting bases of striae 6 and 7; striae narrow, deep with setiferous punctures hardly discernible. Metepisternum microfoveolate with some scattered foveolae unisetose. Hind coxa microfoveolate, setose, short area near trochanteral insertion with setose foveolae, small elongate lustrous area on anterior portion. Hind femur constricted basally and apically, expanded medially to about width of coxa, with very shallowly sulcate ventral margin, with one small, sharp spine on inner margin of sulcus one-fourth from apex of femur ( Fig. 2 ); tibia with lateral and ventral carinae, inner face convex; apex with five spinules, outer lateral and inner ventral spinules subequal, others smaller; claws lobed at base.

Abdomen. First abdominal sternum three times as long as second; second, third and fourth subequal; fifth slightly longer and slightly emarginate mesally; all segments, except the first, with a line of strong, black setae. Pygidium ovate and convex.

Size. Length (pronotum-elytra) 1.5 to 2.25 mm. Width 0.87 to 1.5 mm. Maximum thoracic depth 1.11 to 1.29 mm.

Genitalia. Median lobe with ventral valve deltoid, dorsal valve membranous; internal sac clothed anteriorly with minute spines, armature formed by large cluster of strong spines interrupted mesally by group of finely dentate scales ( Fig. 13 ). Lateral lobes armed at apices with stout spines, lobes cleft to 0.45 their length ( Fig. 14 ).

Female. Similar to male except inner face of hind tibia flat, with lateral, dorsal and ventral carinae well developed, fifth sternum not emarginate; pygidium with triangular gray spot in middle of base flanked by pale yellow spot, faint brown, transverse median band interrupted by median line of gray; paired vague brown spots near apical margin.

Size. Length (pronotum-elytra) 2.04 to 2.10 mm. Width 1.2 mm. Maximum thoracic depth 1.05 to 1.2 mm.

Host Plants. Old records: Condalia correllii M. C. Johnston ( Johnson 1978:436; Udayagiri and Wadhi 1989:96). C. globosa I. M. Johnston (Hetz and Johnson 1988:137) . C. globosa var. pubescens I. M. Johnston (Center and Johnson 1976:200; Johnson 1978:436; Udayagiri and Wadhi 1989:96). C. hookeri M. C. Johnston ( Johnson 1995:42) . C. hookeri var. hookeri M. C. Johnston ( Johnson 1978:436; Udayagiri and Wadhi 1989:96). C. spathulata A. Gray ( Johnson 1978:435; Hetz and Johnson 1988:135; Udayagiri and Wadhi 1989:96). C. warnockii var. kearneyana M. C. Johnston ( Johnson 1978:434; Udayagiri and Wadhi 1989:96).

Condalia hookeri M. C. Johnston is the valid name for C. obovata Hook. ( Kingsolver 1964:111; Udayagiri and Wadhi 1989:96).

New Records: None

Distribution. Old Records: USA (Arizona, California, and Texas) ( Johnson 1978; Kingsolver 1964).

New Records: Mexico (Nuevo Leon, Queretaro, San Luis Potosi, and Veracruz) .

Discussion. Neltumius texanus is more similar to N. dospatrias than to N. arizonensis and N. gibbithorax . See discussion of N. dospatrias for differences between the two species.

The great difference in the Rhamnaceous host plants preferred by this species and N. arizonensis and N. gibbithorax that prefer seeds of Prosopis is remarkable. Johnson (1978, 1989, 1995) discussed the probable origins of these closely related species feeding in plants in different families, and the ecology of N. texanus in more detail.

Figures

Figs. 1–2. Neltumius spp. 1) Antenna; 2) hind femur, medial view.

Figs. 13–14. Neltumius texanus, male genitalia. 13) Median lobe, ventral view; 14) lateral lobes, ventral view.