How to identify oil beetles ?

[D.Liekis]

Greetings,
I need to identify this 4 species of oil beetles which lives in Lithuania:
Meloe proscarabaeus L.
Meloe violaceus Marsh.
Meloe brevicollis Panz.
Meloe variegatus Donov.
It would be grate to know morphological difference between them. And i still don't know on what plant imagos are feeding.

Big thanks!

 

[lukatsi]

Here's part of the key from Móczár László - Állathatározó I. (a great work on Hungarian invertebrates) chapter Meloidae. I tried to be as exact as I can, hope this helps:

12. Male’s antennae more, female’s is less widened, but the last 4 segments are narrow, male’s segment 6 and 7 are sometimes distorted. Pronotum is longer or almost longer than it’s width. ->13.

- Both genders’ antennae segments are of the same width, last four segments aren’t thinner. ->15.

13. Elytra very gently reticulate, with unctuous lustre, sparsely with big dots. Pronotum’s surface is flat. Male’s and female’s antennae almost alike, segments aren’t distorted. Black in color with violet or blue shine. In autumn, 8-23 mm. Meloe autumnalis

- Elytra rugose, wrinkles slur. Pronotum domed, heavily punctated. Male’s antenna segment 6 and 7 are distorted. ->14.

14. Head and pronotum are heavily punctate, elytra are heavily rugose. Blackish blue in color. In spring, 11-35 mm. Meloe proscarabaeus

- Head and pronotum are gently and sparsely punctate, between dots are very gently reticulate without shine. Elytra’s gentle wrinkles are directed longitudinally. In forest clearings and on borders of forests, 10-32 mm. Meloe violaceus

15. Dusty ore green in color, sides of the head and pronotum are copper red, underside of abdomen bluish green, with 1-1 green and copper red spot on the upper segments. Very heavily punctate, elytra rugose. In grassy places, 11-38 mm. Meloe variegatus

- Here are keys of 9 other species, but if you don’t mind I won’t type them all
So: Head and pronotum without hairs, heavily and sparsely punctate, elytra rugose. Body is blue. In mountains and hills, 7-24 mm. Meloe brevicollis


I had to find M. variegatus, they are so beautiful in pictures.