It is hard to tell the adult Himacerus apterus apart from similar species. The Ant Damsel Bug for instance looks identical, but actually has shorter antennae. It is a good way of telling these species apart. The one with antennae shorter than its body or exactly the same size is the Ant Damsel Bug. Should the antennae be longer than the animal's body, you are holding a Himacerus apterus. The wings are usually not fully developed and very short. The animal is not able to fly. Adult Himacerus apterus are some 8 to 11 mm long.
The larvae are wingless smaller copies of the adults. They don't look like ants at all, as can be seen in the bottom picture. They may be seen in May and June mainly, from July to October one may find the adults. These are slow moving predators, climbing on plants and shrubs. They hunt for small insects and spiders, but will suck on plants when no prey is available. The eggs, which are being laid by the end of September or in October, are placed in small holes in the stems of plants. It's the egg overwintering.