Sminthuridae:


Their bodies are picked up and globular. The first four abdominal segments are fused to the thoracic segments and constitute the large abdominal, the last two abdominal segments forming the small abdominal. The antennas are longer than the head.

Neelidae:


They are represented by a single family (Neelidae), very small (average 0.5 mm), they have no eye plate but have a structure comparable to that of Symphypleones, with the difference that their body is an extension chest and not the abdomen and that their antennae are shorter than their head.