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Megascolia maculata (8)
NikosR Gold Star Critiquer/Gold Note Writer [C: 76 W: 3 N: 447] (3436)
Megascolia maculata (Fabricius, 1775)
Hymenoptera: Scoliidae
Common name: Mammoth wasp

Mammoth wasp is the biggest European wasp in Hymenoptera order reaching 5-6cm. It is a parasitic insect parasitizing Rhinoceros beetle (Oryctes nasicornis). Female is bigger than male. The head of female is yellow or orange color. That in picture is a female feeding on pollen of Oreganum sp.
Both have two yellow bands on their abdomens, which can be divided to form 4 spots as it is shown on the photo in WS. Nevertheless, they hold no harm to humans despite their size, in contrast to common wasps and hornets. Indeed, mammoth wasps do have stings, but not for self-defence or nest protection (in fact, they are solitary wasps). You may see several of these wasps flying around decaying tree stumps, they have a purpose there. They’re searching for larvae of Rhinoceros beetle (lat. Oryctes nasicornis), The female wasp once she has discovered the huge larvae, will sting one to paralyze it and then lay her egg on the outer skin. After hatching, the larvae of the mammoth wasp starts eating its host, till reaches the size it could create a cocoon, where it can safely sleep through all winter. 6 months later, the larvae turns into pupa and after 1 month more, from under the underground emerges newly formed mammoth wasp. The adult once feed on flower nectar.

Altered Image #1

NikosR Gold Star Critiquer/Gold Note Writer [C: 76 W: 3 N: 447] (3436)
Another view
Edited by:NikosR Gold Star Critiquer/Gold Note Writer [C: 76 W: 3 N: 447] (3436)

I posted a view of abdomen with thethe four yellows spots, characteristic spots for ID