EN
Mites of the family Syringophilidae are small and uniformly shaped arthropods, inhabiting feather quills of many birds species. Anomalies of setae arrangement are frequently observed in this mite group. Detailed investigation of nymphs and adults Torotrogla merulae Skoracki et al., 2000, reveals the most considerable variability of chaetotaxy aspect in this family. The purpose of our examination is to document anomalies in number and configuration of setae and to hypothesize the possible factors inducing them. As an explanation, a theory based on ‘fluctuating asymmetry’ is proposed.