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Silvanus difficilis
Silvanus difficilis is a species of silvan flat bark beetle widespread in Oriental region. It is introduced to Australia via timber and also to Costa Rica.[1][2] DistributionMany Oriental countries including, Malaya, India,[3] Sri Lanka, Vietnam, Taiwan, Singapore, Sumatra, Java, Christmas Island, Sarawak, Borneo, Philippines, Moluccas, and New Guinea. Also found in Oceanian regions of Solomon Islands, Samoan Islands, and introduced to Australia.[4] There are records from West Africa, Britain,[5] New Ireland and Costa Rica.[6] DescriptionExtremely variable species in appearance, very similar to Silvanus lewisi, Silvanus robustus and Silvanus productus. Two distinct forms are described and identified: 'Normal form' and 'New Guinea form'. The 'Normal form' clearly identified from the 'New Guinea form' due to its short temple, and wider and shorter prothorax.[6] Average length is about 2.17 to 2.64 mm. Body elongated, and slightly depressed. Body color ranges from dull brown to yellow-brown and covered with short, semi-erect, golden pubescence. Head broader than long. Punctures on frontal triangle often ocellate. Eyes are large with temples as long as eye-facets. Antennae broad and clubbed. Pronotum broad and more elongate. Pronotum puncturation is coarse and dense, similar to head. Prosternum with tuberculate surface which become rugose towards sides.[1] Prothorax convex, and elongated. Scutellum large, transverse and pubescent.[6] EcologyAdults have been collected from Shorea robusta in India. They have found among commodities imported to Britain from the Oriental region.[1] References
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