Xyloryctes lobicollis Bates, 1888

Morelli, Enrique & MorÓn, Miguel A., 2003, Descriptions of XYLORYCTES Hope Larvae with a Key to Species Based on the Third Stage Larvae (Coleoptera: Scarabaeidae: Dynastinae), The Coleopterists Bulletin 57 (3), pp. 289-295 : 292-293

Xyloryctes lobicollis Bates

Third Instar Larva ( Figs. 15–25 ). This description is based on the exuvium of one third instar larvae from ‘‘ MÉXICO: Chiapas, Chiapa de Corzo, Mirador Cañón del Sumidero, 1,340 m elevation, 14-X-1978, J. Valenzuela, rotten log with nest of Neoponera villosa (Formicidae) , deciduous tropical forest’’ reared to adult stage. Pupal stage at 2-III-1979. Adult stage at 16-IV-1979. The specimen is deposited at the

collection of Department of Entomology , Instituto de Ecología, A.C. Xalapa, Veracruz, México ( IEXA) .

Description. Maximum width of head capsule: 9.3 mm. Cranium ( Fig. 15 ). Color dark reddish brown. Surface sparsely punctate. Epicranium with 1 dorsoepicranial setae on each side. Clypeus. Rounded, with 2 central setae and 1 lateral seta on each side. Labrum. With 2 anterior labral setae, and 2 lateral labral setae on each side. Epipharynx ( Fig. 16 ). Corypha with 4 stout setae. Acanthoparia with 6–7 short setae. Chaetoparia with 28–34 setae on each side. Dexiotorma widened toward lateral border. Laeotorma well-developed, with pternotorma wide and rounded, clearly defined. Haptolachus simple, with sensorial cone. Maxilla ( Fig. 17 ). Stridulatory area with row of 7 rounded teeth and a distal, truncate process. Labium ( Fig. 18 ). Dorsal surface with 42 spine-like setae of different length. Hypopharyngeal sclerome asymmetrical with 9–17 setae on each side. Mandibles. Left mandible ( Figs. 22–23 ) with 2 scissorial teeth anterior to scissorial notch and 1 scissorial tooth posterior to notch. Stridulatory area widened, length 2.1 times its width. Lateral edge with 5 setae. Molar area bilobed, dorsomolar area with 3 short setae. Brustia consisting of 5 setae Right mandible ( Figs. 24–25 ) with 2 wide, scissorial teeth, stridulatory area slightly smaller than that of left mandible. Lateral edge with 7 setae. Molar area trilobed. Antennae ( Figs. 19–20 ). Surface on last segment with 5 dorsal sensoy spots and 10 ventral sensory spots. Thorax. Prescuta of meso- and metathorax bare. Thoracic spiracles with C-shaped respiratory plate, 1.12 mm high and 0.91 mm wide; distance between 2 lobes of respiratory plate less than dorsoventral diameter of bulla; plate with 26 holes across diameter at middle, holes suboval. Bulla of all spiracles slightly convex. Abdomen. Spiracles of abdominal segments I–VIII similar in size. Dorsa of abdominal segments I–VII covered with 25–35 short, spine-like setae and some, scattered, long setae. Dorsa of abdominal segments VIII–IX only with 1 posterior transverse row of 8 slender, long setae. Raster with teges of 32 curved setae. Lower anal lip with 40 short setae and a caudal fringe of 14 long setae. Legs. Tarsal claws each bearing 1 preapical seta on each side ( Fig. 21 ).

Figures

Figs. 15–21. Xyloryctes lobicollis, third instar larva. 15) Frontal view of head; 16) epipharynx; 17) Right maxilla, dorsal view; 18) labium and hypophanyngeal sclerome, dorsal view; 19) apical antennal segment, dorsal view; 20) same, ventral view; 21) metatarsungulus, lateral view. Scale lines: Figure 15 ¼ 2 mm; Figure 16 ¼ 1 mm; Figures 19–20 ¼ 0.5 mm.

Figs. 22–25. Xyloryctes lobicollis, third instar larva. 22) Left mandible, dorsal view; 23) left mandible, ventral view; 24) right mandible, ventral view; 25) right mandible, dorsal view. Scale line ¼ 2 mm.