Phytholaema dilutipes

Ernesto, Cisternas A. & Roberto, Carrillo Ll., 2010, Description of the Larvae ofPhytholaema herrmanniGermain andPhytholaema dilutipes (Fairmaire and Germain) (Coleoptera: Scarabaeidae: Melolonthinae), The Coleopterists Bulletin 64 (2), pp. 141-147 : 143-147

Phytholaema dilutipes

(Fairmaire and Germain, 1860) Third instar ( Figs. 16–30 )

The description is based on larvae collected from a pasture near Curepto, 7 a Región del Maule 35°2´S and 72°4´W at 10 m elevation.

Description. C-shaped. Head: width of cephalic capsule L 1: 1.43± 0.09 mm (n = 4), L 2: 2.05± 0.18 mm (n = 4), and L 3: 3.6± 0.11 mm (n = 10); without ocellus. Cranium ( Fig. 16 ): smooth, shiny, light yellow; frontal suture whitish, bisinuate, forming a sharp angle at the joint; epicranial suture 1/3 length of frontal suture; 4–5 dorso-epicraneal setae and 5 lateral setae on each side; 2 anterior setae and 3 frontal posterior setae; 1 seta anterior to antennal socket; 7–8 long setae lateral to antennal socket viewed from the front. Antenna ( Fig. 17 ): four antennomeres; apical antennomere with 1 dorsal sensory spot and 2 ventral sensory spots; second antennomere 1.5–1.8× longer than first antennomere; third antennomere with elongated process with 1 ventral sensory spot. Clypeus ( Fig. 16 ): trapezoidal; surface of preclypeus smooth, without setae; smooth postclypeus with 2 long setae, 2 medium-length external setae and 2 clypeal setae. Labrum ( Fig. 16 ): pentagonal, symmetrical, trilobed, apical lobe with a pair of blunt setae; with 6–10 posterior setae; 4 medial setae and 10 anterolateral setae present. Epipharynx ( Fig. 18 ): pentagonal; plegmatia and proplegmatium absent; sclerotized epizygum closely connected to the right zigum, left zigum absent; corypha with 2 blunt setae; clithrum present; haptomerum with 9–11 sensilla and 3–4 heli in a transverse row; acanthoparia with 8–10 sickleshaped, short setae; gymnoparia without setae; haetoparia setose; dexiotorma and laeotorma well developed and sclerotized, without apotorma and epitorna; pternotorma present; laeotorma one-half length of dexiotorma; haptolachus with 2 nesia; crepis present. Mandibles ( Figs. 19, 20 ): asymmetrical, left cutting region with 3 teeth and right with 2 teeth; scrobe with 7–8 setae and 2-3 basolateral setae; dorsal carina with 1 seta; dorso-molar area with a group of setae close to molar; left ventral process smaller than right ventral process; calyx elongated; brustia present; acia well developed; stridulatory area absent; ventral processes rough- ened. Maxilla ( Fig. 21 ): galea and lacinia fused and slightly separated at the apex; galea with a well developed uncus; lacinia with 3 unci, the distal 2 fused at the base ( Fig. 22 ); stridulatory area formed by a row of 9–11 rounded teeth ( Fig. 23 ). Labium ( Figs. 24, 25 ): hypopharyngeal sclerome asymmetrical, strongly developed and sclerotized, left hypopharyngeal lobe with a row of vertically oriented setae and proximal area of the scleroma with a row of horizontally oriented setae ( Fig. 24 ); glossa covered by slender and robust setae; subtrapezoidal postmentum with 2 slender setae; posterior prementum with 2 long and 2 short setae, anterior prementum with 2 long setae and 2 short setae and 3–4 lateral setae close to the labial palp ( Fig. 25 ).

Thorax. Spiracles ( Fig. 26 ): C-shaped respiratory plate 0.30 mm long, 0.21 mm wide, with 12–15 irregular and small holes across diameter ( Fig. 27 ); distance between the 2 lobes of the respiratory plate 2/3 diameter of dorso-ventral diameter of bulla. Pronotum: with an irregular, sclerotized shield, yellow on the side, surrounded by18-20 setae, 2–3 very long. Legs ( Fig. 28 ): gradually increasing in size from prothoraxic to metathoracic leg; each tarsungulus affiliated with 2 proximal setae; tarsungulus of metathoraxic leg smaller.

Abdomen. Abdominal spiracles A1-4 of similar size (3.57–3.69 mm), A5, A7, and T smaller (2.76– 2.95 mm), A6 and A8 conspicuously smaller (2.0– 2.35 mm). Dorsum of abdominal segments A2–A6 with 3–6 rows of short setae. Pleural lobe A9 with vestigial sclerotized structure ( Fig. 29 ). Spiracular area with one very long seta and 3–6 short, medium and long setae. Raster ( Fig. 30 ): with 2 parallel, longitudinal palidia with 11–19 pali (n = 10); tegillum with 19–28 hamate setae; septulum narrow and glabrous; anal opening Y-shaped; dorsal anal lobe covered with slender cylindrical setae, mastly short and medium-length; ventral anal lobe with slender cylindrical setae, mainly medium-length and short; campus with 2 moderately long setae; barbula not well defined, with a few slender, long setae.

Figures

Figs. 16–23. Phytholaema dilutipes, third instar. 16) Head, frontal view; 17) Distal antennomere, a) ventral and b) lateral view; 18) Epipharynx; 19) Mandibles, ventral view, a) left and b) right; 20) Mandibles, dorsal view, a) right and b) left; 21) Maxillae, a) dorsal and b) ventral view; 22) Apex of lacinia and galea showing unci; 23) Maxillary stridulatory area. Scale bar in mm.

Figs. 24–30. Phytholaema dilutipes, third instar. 24) Labium, dorsal view; 25) Hypopharynx; 26) Thoracic spiracle; 27) Respiratory plate; 28) Tarsungulus of a) prothoracic leg, b) mesothoracic leg, and c) metathoracic leg; 29) Sclerotized vestigial structure on A9; 30) Last abdominal segment, ventral view of raster. Scale bar in mm.