Pelidnota fulva Blanchard, 1850

Rodrigues, Sérgio Roberto, Morón, Miguel Angel & Nogueira, Gerson Aler de Lima, 2012, Description of the Third Instar ofPelidnota fulvaBlanchard, 1850 (Coleoptera: Scarabaeidae: Rutelinae), The Coleopterists Bulletin 66 (3), pp. 266-270 : 267-269

Pelidnota fulva Blanchard, 1850 , third instar ( Figs. 1–12 )

Material Examined. Three larvae reared from eggs obtained from adults collected at Aquidauana, Mato Grosso do Sul, Brazil by SRR.

Description. Length 54–55 mm. Color light gray becoming white when reaching the prepupal

stage ( Fig. 1 ). Head: Hypognathous. Cephalic capsule 6.54 mm wide ( Fig. 2 ). Epicranial suture and inner frontal suture present. Surface of cranium slightly reticulated with sparse setae, setae predominantly brown. Row of 6 small setae next to epicranial suture laterad frontal suture. Anterior frontal region with 4 setae; posterior frontal region with 3 setae on each side, 2 exterior frontal setae and 2 angular anterior frontal setae on each side. Stemmata absent. Five basal antennal setae on each side. Postclypeal surface with 2 setae on each side and 2 anterior central setae. Labrum with 6 posterior labral setae and 7–9 posterolateral labral setae on each side; anterior margin of labrum with 30 setae ( Fig. 2 ). Epipharynx wider than long ( Fig. 3 ); right acanthoparia with 12 setae; left acanthoparia with 10 setae; haptomeral process with distal projection, 4 rows of setae, and each row with 6–9 setae; zygum absent; plegmata and proplegmata absent; acroparia with 4 thick setae; gymnoparia narrow; chaetoparia well-developed, with more stout setae along the margins at middle, with 92 setae at left and with 52 setae at right; pedium longer than wide; dexiotorma narrow, elongate; laeotorma with highly sclerotized pternotormal process, shorter than dexiotorma; apotormal process absent; nesium absent; sensorial cone present. Mandibles strongly sclerotized; right mandible ( Fig. 4 ) with scissorial region with 1 tooth (S1 + S2 fused) separated from S3 by scissorial notch, scrobe with 11 setae, dorsomolar surface with 12 setae, dorsal surface with 2 long setae below base of S3, brustia with 3 setae, preartis concave, ventral mandible with a wellmarked stridulatory area with about 22 narrowly separated, subparallel ridges, ventral process present, ventral molar area with 11 setae, calx welldeveloped with 9 basolateral setae basolateral; left mandible ( Fig. 5 ) with scissorial area with 2 apical teeth separated by scissorial notch, scrobis with 12 setae, acia well-developed, dorsomolar surface with 8 setae; ventral surface with stridulatory area with about 24 narrowly separated, subparallel ridges, ventral process large and rounded, brustia with 8 setae, molar lobe well-developed. Maxilla with galea and lacinia fused; galea with apical uncus and many thick, slender setae on dorsal and ventral regions; lacinia with apical uncus and various long, thick, dorsal and ventral heli; stipes with numerous long, ventral setae, and dorsal region with shorter setae; maxillary stridulatory area with row of 13 acute denticles, anterior denticles wider; maxillary palps 4-segmented ( Figs. 6 and 7 ). Labium with 17 long setae and 40 short setae on glossa; hypopharyngeal sclerome asymmetrical, strongly developed on right side; left lateral lobe with 23 setae and right lateral lobe with 7 setae ( Fig. 8 ). Antenna with antennomeres 1–2 long, second antennomere more dilated at the apex; antennomere 3 with small, ventral projection; antennomere 4 short, with 8 sensorial areas, 4 dorsal and 4 ventral ( Fig. 9 ). Thorax: Pronotum formed by a single lobe, meso- and metanotum with 3 lobes. Thoracic segments with several small dorsal and lateral setae. Prothoracic spiracle C-shaped, 1.8 mm long, 1.0 mm in wide, in reverse position of the abdominal spiracles; respiratory plate with about 28 irregularly margined holes across diameter at middle ( Fig. 10 ). Lateral prothoracic sclerotization evident, irregularly shaped, longer than wide. Anterior and middle legs slightly smaller than posterior legs ( Fig. 11 ); coxa, trochanter, femur, tibia, and tarsus with stout setae; all tarsunguli similar in size, anterior 0.22 mm long, middle 0.24 mm, and posterior 0.16 mm, each with 2 setae, 1 apical and 1 medial. Abdomen: Ten-segmented. Spiracles I, II, IV, and VIII similar in size (0.5 mm long, 0.4 mm wide); spiracles V, VI, and VII (0.4 mm long, 0.3 mm wide) slightly smaller than spiracles I, II, IV and VIII; spiracles III (0.3 mm long, 0.4 mm wide) smaller than other spiracles. Spiracles surrounded by 2–11 setae ( Table 1). Raster: Palidia absent, with teges formed by about 26–27 short and medium sized setae mixed. Lower anal lip with 45 short, spine-like setae and 42 slender, long setae ( Fig. 12 ).

Ritcher (1966) and Jameson and Morón (2001) characterized the larvae of the tribe Rutelini as having: stipes of the maxilla with a dorsal row of 5–14 sharp, conical, or recurved stridulatory teeth and with an anterior process; lacinia with 1–2 unci; epipharynx with haptomerum mound-like or beaklike and with a group of 15 or more spine-like setae; epipharynx with one or two nesia present; proplegmata absent; plegmata present or absent; dorsal surface of last antennal segment with two or more dorsal sensory spots; raster with or without palidia; and palidia polystichous. The third instar of P. fulva is distinguished from larvae of other species of Pelidnota by the acroparia of the epipharynx with four thick, spine-like setae, three irregular rows of heli, and the acanthoparia formed by 10–12 short, thick, curved setae. The cranium has four anterofrontal setae and six dorsoepicranial setae. However, larvae of P. virescens and P. punctata are very similar.

Figures

Figs. 1–5. Pelidnota fulva, third instar. 1) Larva, lateral view; 2) Head, frontal view; 3) Hypopharynx; 4) Right mandible, a) ventral view, b) dorsal view; 5) Left mandible, a) dorsal view, b) ventral view. Fig. 1 scale bar = 2 mm; scale bars in other figures = 1 mm.

Figs. 6–10. Pelidnota fulva, third instar. 6) Left maxilla, a) dorsal view, b) ventral view; 7) Right maxilla, a) ventral view, b) dorsal view; 8) Hypopharynx; 9) Antenna, dorsal view; 10) Prothoracic spiracle. Scale = 1 mm.

Figs. 11–12. Pelidnota fulva, third instar. 11) Left legs, a) prothoracic, b) mesothoracic, c) metathoracic; 12) Raster. Scale = 1 mm.