Golden Stag Beetle

Black Bess Beetle
Brown Bess Beetle

Black Dung Beetle
Greed Dung Beetle
Punctated Dung Beetle 
Green Scarab Beetle
Brown Cockchafer
Yellow Cockchafer
Nectar Scarab Beetle 
Common Christmas Beetle
White Christmas Beetle
Golden Christmas Beetle
Green Christmas Beetle 
Black Nail Beetle
Small Brown Scarab
Small Black Scarab 
Rhinoceros Beetle
Cowboy Beetle
Red-brown Flower Beetle
Fiddle Beetle
Spotted Flower Chafer
Brown Flower Beetle
Mango Flower Beetle


Black Bess Beetle - Mastachilus sp.

Family Passalidae

This page contains information and pictures about Black Bess Beetles in family Passalidae that we found in the Brisbane area, Queensland, Australia.

Body length  40mm
The Bess Beetle is shiny, black to dark brown in colours with parallel grooves on wing-covers. There is a small horn on its head. 
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On Jan 2009 in Brisbane Koala Bushlands near Burbank, we found two Bess Beetles got caught on spider web. One beetle was fully warped around by spider silk and one just entangled on web. Both were still struggling. The spider web is a large orb web could be belonged to a large Garden Orb Weaver or similar.  The spider was not there. The spider could not hurt the beetles anyway, except keep them on the web. 
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We removed the two beetles from the web and clean the silk. For the fully warped beetle, we needed to carefully remove the silks using a knife. 
One beetle gave me a bite when I held it on hand. Its mandibles were not sharp and did not cut into my skin. On my hand, they kept making the loud stridulation noise and I can feel the vibration as well.  
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Both beetles walked off my hand and dropped onto the ground. They quickly walked into the plant materials and hide away.
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Since two beetles got caught by the spider which build web only at night time, this indicated that the Bess Beetles could be a night time active flier.  

1. Insects of Australia, CSIRO, Division of Entomology, Melbourne University Press, 2nd Edition 1991, p 627.
2. Insects of Australia and New Zealand - R. J. Tillyard, Angus & Robertson, Ltd, Sydney, 1926, p226.
3. Beetles of Australia - Trevor J Hawkeswood, Angus & Robertson Publishers, 1987, Plate 48.
4. Passalidae - Australian Biological Resources Study, Department of the Environment, Water, Heritage and the Arts, 2008.
5. A Bit About Beetles In Brisbane - by Geoff Monteith, Save Our Waterways Now, 2008.
6. Passalidae - Insects of Townsville, Australia - Graeme Cocks  

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Last updated: September 11, 2011.