Schizochelus modestus Philippi

Ernesto Cisternas, A. & Roberto Carrillo, Ll., 2012, Descriptions of the Third Instars ofPristerophora picipennis (Solier) andSchizochelus modestusPhilippi (Coleoptera: Scarabaeidae: Melolonthinae: Macrodactylini) from Southern Chile, The Coleopterists Bulletin 66 (2), pp. 131-138 : 133

Schizochelus modestus Philippi third instar ( Figs. 15–28 )

The description is based on 10 larvae that were reared from eggs laid by adults collected in flight in pastures near Puerto Varas, S41°23′ W73°00′, at 91 m elevation, and were collected from locations including Osorno, Río Bueno, Ranco, and Puyehue, all located in the Región de Los Lagos and Región de Los Ríos.

Description. C-shaped. Width of head capsule L 3: 1.67 ± 0.08 mm (n = 10). Without ocellus. Cranium ( Fig. 15 ): Smooth, shiny, light yellow; frontal suture whitish, bisinuate, forming a sharp angle at joint; epicranial suture 1/3 length of frontal suture; 2 dorsoepicranial setae; 2 frontal anterior and 2 frontal posterior setae; 1 seta adjacent to antennal socket; 6–7 long setae adjacent to lateral antennal socket (viewed from the front). Antenna ( Fig. 16 ): With four antennomeres. Apical antennomere with 1 dorsal sensory spot and 2 ventral sensory spots. Second antennomere 1.8X as long as first antennomere. Third antennomere with elongate process with 1 ventral sensory spot. Clypeus ( Fig. 15 ): Trapezoidal. Surface of preclypeus smooth, without setae. Smooth postclypeus with 2 lateral setae, 1 very long and 1 mediumlength, and 2 clypeal setae. Labrum ( Fig. 15 ): Pentagonal, symmetrical, trilobed, apical lobe with pair of blunt setae; with 2 posterior setae, 4 medial setae, and 2 setae on the anterior margin. Epipharynx ( Fig. 17 ): Pentagonal. Plegmatia, proplegmatium, epizygum, and zygum absent. Corypha with 2 blunt setae. Clithrum present. Haptomerum with 5–7 sensilla and 3–4 heli in a transverse row. Acroparia with long, thick setae. Acanthoparia with 5–7 sickle-shaped, short posterior setae and 3 straight anterior setae. Gymnoparia without setae. Chaetoparia covered with setae. Pterotorma dexiotorma and laeotorma well-developed and sclerosed, without apotorma and epitorma. Dexiotorma 1.25X length of laeotorma. Haptolachus with 2 nesium. Crepis absent. Mandibles ( Figs. 18, 19 ): Asymmetrical. Left cutting region with 3 teeth and right with 2 teeth. Scrobe with 4–5 basolateral setae. Dorsal carina without seta. Dorso-molar area with a group of short setae close to molar surface. Right ventral process smaller than left ventral process. Calyx elongated. Brustia present. Acia well-developed. Stridulatory area absent. Ventral processes with roughness. Maxilla ( Fig. 20 ): Galea and lacinia fused, slightly separated at the apex; galea with well-developed uncus; lacinia with 3 unci, the 2 distal unci fused basally ( Fig. 21 ). Stridulatory area formed by a row of 8–10 teeth ( Fig. 22 ). Labium ( Figs. 23–24 ): Hypopharyngeal sclerome asymmetrical, strongly developed and sclerosed, left hypopharyngeal lobe with a row of horizontal setae and proximal area of scleroma with a row of vertical and horizontal thick setae ( Fig. 23 ). Glossa covered by slender setae and robust setae. Subtrapezoidal postmentum with 2 slender setae. Posterior pre- mentum with 2 long setae, anterior prementum with 6 slender setae and 1 lateral seta close to the labial palp ( Fig. 24 ). Thorax. Spiracles ( Fig. 25 ): C-shaped, respiratory plate 0.12 mm long, 0.05 mm wide, with 10–12 regular holes across diameter ( Fig. 26 ). Distance between 2 lobes of respiratory plate similar to dorsoventral diameter of bulla. Pronotum: With irregular sclerosed shield, yellow on the side, surrounded by 15–20 long, medium, and short setae. Dorsum of prothorax with 1 irregular row of long, medium, and short setae. Legs ( Fig. 27 ): Gradually increase in size from prothorax to metathorax. Each tarsungulus affiliated with 2 proximal setae. Metatarsungulus smaller than preceding tarsunguli. Abdomen: Spiracles on A1 (0.09 mm) and A2–8 (0.07 mm) of similar size. Spiracular area with one very long seta and 4–6 short, medium, and long setae. Dorsum of A1–6 with 3–4 rows of short, sickle-shaped setae. Raster ( Fig. 28 ): With 2 parallel, longitudinal palidia with 9–10 pali (n = 10). Tegillum with 13–16 hamate setae laterally. Septulum bare. Anal opening Y-shaped. Dorsal anal lobe covered with sickle-shaped setae mixed with straight, thin, small setae. Ventral anal lobe with straight, slender setae. Campus with 2 moderately long setae. Barbula with a few long setae.

Figures

Figs. 15–22. Schizochelus modestus, third instar. 15) Head, frontal view; 16) Distal antennomere, a) dorsal, b) ventral, c) lateral view; 17) Epipharynx; 18) Mandibles, ventral view, a) left, b) right; 19) Mandibles, dorsal view, a) right, b) left; 20) Maxillae, a) dorsal view, b) ventral view; 21) Apex of lacinia and galea showing unci; 22) Maxillary stridulatory area. Scale bar in mm.

Figs. 23–28. Schizochelus modestus, third instar. 23) Labium, dorsal view; 24) Hypopharynx; 25) Thoracic spiracle; 26) Respiratory plate; 27) Tarsungulus of a) prothoracic leg, b) mesothoracic leg, and c) metathoracic leg; 28) Last abdominal segment with raster, ventral view. Scale bar in mm.