Life in a Southern Forest

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Rhopaea verreauxi (Cocksfoot Grub), Melolonthinae

Workbook


Identification to subfamily Melolonthinae (Chafers)

- from Hangay, G. and Zbrorowski, P. “A Guide to Beetles of Australia”. CSIRO Publishing 2010

- CSIRO “The Insects of Australia” 2nd Ed. 1991 p. 628

Fig. 1

  • Tarsal claws equal and fixed (contrast unequal and moveable claws of Rutelinae) - Fig. 1

  • Mandibles completely concealed from above

  • Externally visible sclerotised labrum - Figs. 1, 3

Fig. 2. arrow shows most posterior spiracle visible beneath elytra

  • Only one pair of abdominal spiracles (most posterior) visible beneath edges of elytra - Fig. 2

  • Tarsal claws often toothed - Fig. 6

  • Head and pronotum in males simple i.e. lacking horns and other protrusions - Fig. 5a,b,c


Identification to genus Rhopaea

- from Britton, E.B. (1978) “A revision of the Australian chafers (Coleoptera: Scarabaeidae: Melolonthinae) vol 2. Tribe Melolonthini.” Aust. J. Zool. Suppl. Ser. 60, 1-50

Fig. 3

  • anterior face of clypeus bears scattered punctures beneath the setae all over its surface - Fig. 3

  • anterior edge of the clypeus as seen from above straight or convex in the middle, never broadly bilobed - Fig. 3

Fig. 4 antenna dissected from male, length of club = 2.8mm: normal range = 2.6-3.6mm

  • antenna 10-segmented with a 5- to 8- lamellate club - Fig. 4

  • lamellae much longer in male than in female (female range = 1.27-1.7mm)

  • head, pronotum and elytra clothed in short, fine, semi erect setae, sometimes with sparse, long, erect, setae in addition - Fig. 5a,b,c

  • never bearing scales

  • pronotum without defined or raised anterior and posterior margins - Fig. 5b,c

Fig. 6 tarsus of right middle leg showing outer claw

  • tarsal claws each with a strong tooth in the middle - Fig. 6


Identification to species level Rhopaea verreauxi

- from Britton, E.B. (1978) “A revision of the Australian chafers (Coleoptera: Scarabaeidae: Melolonthinae) vol 2. Tribe Melolonthini.” Aust. J. Zool. Suppl. Ser. 60, 1-50

  • body length in above images = 21mm: normal range = 19-29mm

  • colour: dark brown with anterior part of clypeus and lateral margins of pronotum reddish - Figs. 5a,b,c

  • antennae, legs and ventral surface yellowish brown - Figs. 5a,b,c,d

  • male antennal club 2.8mm long (maximum length female antennal club = 1.7mm)

  • antennal segment 4 subconical without trace of a lamina, width across axis 0.6mm - Fig. 4

  • antennal segment 3 elongate, cylindrical - Fig. 4

  • morphology of aedaegus (Fig. 7a,b) matches images in Britton (1978) - compare Figs. 147 (ventral view), 148 (dorsal view) and 149 (lateral view) below .

  • distribution - NSW and southern Queensland, mainly within 50km of the coast.


Individual shown here was collected on 18/12/18 at around 10pm

Text and images from Britton, E.B. (1978) “A revision of the Australian chafers (Coleoptera: Scarabaeidae: Melolonthinae) vol 2. Tribe Melolonthini.” Aust. J. Zool. Suppl. Ser. 60, 1-50

List of Australian Rhopaea species

Rhopaea magnicornis, claws


This is a workbook page … a part of our website where we record the observations and references used in making species identifications. The notes will not necessarily be complete. They are a record for our own use, but we are happy to share this information with others.