Excerpt: There has been much recent interest in the comparative morphology of the Heteroptera. This work has emphasized the land bugs, or Geocorisae, and has been concerned with working out the relationships and taxonomic placement of the higher categories (categories above the genus), and with the phylogenetic lines and sequences of these higher categories. The geocorisine groups with which I have been most concerned are in the closely related superfamilies Lygaeoidea, Pyrrho- coroidea, and Coreoidea (see Schaefer, 1964, for a discussion of the relationships among these groups). Another superfamily, the Pentatomoidea, is less closely related. All four of these superfamilies have arolia and pseudarolia, and all four have trichobothria. Because they possess this last character in common, the four are grouped together under the name Heteroptera Trichophora (Tullgren, 1918), aname of no nomenclatorial standing but nevertheless convenient.
Trichobothria are long hairs arising from often darkened sockets on the relatively bald abdominal venter. They are usually easy to distinguish from other hairs, because they are longer, have a darkened base, and are arranged symmetrically in a distinctive pattern on each segment.
These patterns and the number of trichobothria in them are characteristic of the higher categories of the Trichophora. Since the trichophoran families are closely related, and since this close relation- ship has been established on evidence from other morphological features than trichobothria, one might look for phylogenetic significance in the variety of patterns. However, very little is known about the function and phylogenetic origin of trichobothria. I shall speculate here on their function and their phylogenetic significance, but more must be learned about trichobothria before speculation becomes knowledge.
Schaefer, Carl W.
"Some Notes on Heteropteran Trichobothria,"
The Great Lakes Entomologist, vol 1
Available at: https://scholar.valpo.edu/tgle/vol1/iss3/2