Canthon muticus muticus Harold, 1868

Morelli, Enrique & González-Vainer, Patricia, 2011, Canthon (Pseudepilissus) Muticus MuticusHarold, 1868 (Coleoptera: Scarabaeidae): Descriptions of the Third Instar and Pupa, The Coleopterists Bulletin 65 (4), pp. 371-375 : 371-375

Canthon muticus muticus Harold, 1868 , third instar ( Figs. 1–15 )

Description. Body C-shaped, slightly humped dorsally ( Fig. 1 ). Length 17 mm; width at abdomi-

nal gibbosity 7 mm. Cranium ( Fig. 2 ): Maximum width of head capsule 3.5 mm. Surface of cranium finely punctate, light yellow-brown; surface area of the clypeus, labrum, and mandibles pigmented. Epicranial suture marked; frontal suture extending

5) Antenna; 6) Raster.

ridge extended to incisive area. Lateral area with 3 setae. Left mandible ( Figs. 10–12 ) with narrow base and 3 scissorial teeth, apical one longest. Molar area with a prominent, conical tooth; stridulatory ridge short. Maxilla ( Fig. 13 ): Palp 4-segmented, apical segment conical. Stridulatory area on dorsal face of stipes ( Fig. 14 ), with 8 teeth arranged in uneven row, 3 lateral setae, and 3 anterior setae. Galea with apical mucro; with 10 thick mesal setae and 5 lateral setae; 7–10 thick mesal setae aligned from mucro to base. Lacinia with sclerotized, conical uncus; 1 seta on base of uncus and 1meso-ventral seta; with row of 5 elongated ventral setae and 6 exterior setae. Labium-hypopharynx ( Fig. 15 ): Oncyli asymmetrical, strongly sclerotized, left side larger; both oncyli framed by microsensillae, with 6–8 short setae on right side. Central lobe of glossa with 4 long and 4 short setae on each side. Lateral right lobe with 3 thick, pointed setae and 4–6 thin, long setae; left lateral lobe with 11–13 long setae. Antennae ( Fig. 5 ): Four-segmented,third segment with conical sensory organ; last segment markedly small. Thorax: Prothoracic shield with anterior, angular projection on each side. Abdomen: Raster ( Fig. 6 ) with 24 short, inconspicuous teges on each side arranged in two irregular areas defining a pseudoseptular area.

16) Dorsal view; 17) Ventral view.

to base of antenna. Vertex with basal group of microsensilla. Epicranium with 3 dorsal setae and group of 3 lateral setae on each side. Frons on each side with 1 posterior frontal seta, 2 exterior frontal setae, and 1 seta in anterior angle. Fronto-clypeal suture rectilineal. Labrum ( Fig. 3 ): Strongly trilobed, width 2X length, with 4 anterior setae, 4 posterior setae, 3 lateral anterior setae, and 2 interior setae on each side. Epipharynx ( Fig. 4 ): Dexiotorma and laeotorma merged with rhomboidal epitorma. Protophobea with row of short, compact sensilla. Chaetoparia with 4 short setae. Mandibles: Thick and asymmetric. Right mandible ( Figs. 7–9 ) with broad base and 2 rounded, unequal scissorial teeth separated by a groove and single seta on lateral margin. Molar area irregularly lobed. Ventral surface with a stridulatory

Figures

Figs. 1–6. Canthon muticus muticus, third instar. 1) Habitus; 2) Head, frontal view; 3) Labrum; 4) Epipharynx;

Figs. 7–15. Canthon muticus muticus, third instar. 7) Right mandible, ventral view; 8) Right mandible, frontal view; 9) Right mandible, dorsal view; 10) Left mandible, dorsal view; 11) Left mandible, frontal view; 12) Left mandible, ventral view; 13) Right maxilla, dorsal view; 14) Stridulatory teeth of maxilla, dorsal view; 15) Hypopharynx, dorsal view.