The various Scoliid wasps range from less than 10mm to a magnificent 50mm, such as the Megascolia procer below. (Photo copyright and courtesy of E-Trails Singapore.) They also come in a range of colours; many are beautifully marked with orange, red and yellow on a black ground colour. Many also have dark tinted wings which give off a metallic blue-green sheen under good light.
As previously mentioned, Scoliid wasps prey mostly on beetle larvae. Therefore, female Scoliids can frequently be found digging into the ground or into rotting logs. Scoliids are also not generally common in very urban areas, although they may be found feeding on nectar from flowers in urban parks, or even digging in flowerbeds in search of prey. They are more common in forested areas and grassy scrub or wasteland. In Singapore, they are also well-represented in the mangrove swamps, with several species seemingly confined to such areas!
I have not been able to find anyone who is well-versed with this group. Thus, I have had to rely mostly on various guidebooks for identification; in fact, I have not even attempted to identify some of those I found yet! The following are a number of Scoliids I found in Singapore in 2005.
The photo below is of a small, shiny black Scoliid with a yellow head which is common in mangrove areas in Singapore. I observed them on previous trips but never managed to photograph them. This photo copyright and courtesy of Jacqueline Lau.