Last week-end I was working in my parent's garden and when I dig a bit the ground, I found few larvas I never seen before. My father told me there are there every time when he's doing the garden springtime.
I took some pictures (I just put it on leaves for the picture to see better than on the ground).
And the gallery hi-resolution pictures
The location is in northern of Switzerland (Jura) at around 700 meters above the sea and the larvas were inside the ground in around 3-5 centimeters (1-2 inches) deep.