Phengaris arion - Large Blue - Tijmblauwtje - Quendel-Ameisenbläuling
The male upperside is bright sky-blue, with a broad black border an an arc of wegde-shaped, black post-discal spots on the forewing. The post-discal spots are small or absent on the hindwing and the outer border may consist only of small black spots. Both wings have white fringes. The female is similar, but she has larger post-discal spots and the hindwing generally has a complete black border. The undersides are greyish brown with large black spots, those in the post-discal area of the forewing being distinctly elongate or oval. The wings are often quite shiny and there is a faint clarblue flush at the base of the hindwing. Flight from June to August in one brood. The larval foodplant is Wild Thyme and the caterpillars needs Red Ants. After the third moult, the caterpillars fall to the ground and wait to be discovered by the ants. As soon as an ant starts to nuzzle a caterpillar, the latter exudes a drop of sweet liquid, which is eagerly lapped up by the ant. The ant becomes very excited and coninues to milk the caterpillar for a while and eventually carries it back to its nest. Caterpillars not found by ants within one or two days will die. The caterpillar stays in the nest throughout the winter and pupates there in spring. After emering from chrysalis into butterfly, the butterfly had to leave the ants nest quickly.