Chaetotaxy

Chaetotaxy is the arrangement of bristles (macrochaetae) on an insect or mite, or taxonomy based on their position and size. For example, it is important in Diptera, in which group it was formalised by Ernst August Girschner. The term chaetotaxy was later proposed by Carl Robert Osten-Sacken.

The chaetotaxy of a fly might include :- acrostichal, dorsocentral, humeral, mesopleural, sternopleural, notopleural, postalar, supraalar and scutellar bristles on the thorax; dorsal, posterodorsal, anterodorsal, ventral, posteroventral and anteroventral bristles on the legs and ocellar, orbital, postvertical, vibrissal, outer vertical and inner vertical bristles on the head.