Description from Cott (1957). Both sexes wingless. Body and legs blackish brown; antennal segment I brown with apex paler, II yellowish white, III brown with extreme base paler. Head longer than wide, cheeks convex and sharply constricted to basal neck; compound eyes narrowed and prolonged on ventral surface. Pronotum with 3–4 pairs of rather short pointed major setae, midlaterals not developed. Fore tarsus with tooth. Metanotum elevated medially, with weakly concentric reticulation. Abdominal tergite IX setae S1 blunt, about as long as tube.
Male varying in size. Large male with fore tarsal tooth large, fore femora expanded and L-shaped; tergite IX setae S1 and S2 equal in size.
A total of 27 species are listed in the genus Compsothrips, mainly in tropical countries but with seven described from North America. Of these seven, C. hookeri is widespread across the southern States from Florida to California, two species are from Florida, and four species are from various Western States. These species differ in the color of the basal antennal segments, but given that they are all wingless ant-mimics there must be considerable scope for studies on their behavior, as well as their inter-population variation using molecular data. C. tristis has the third antennal segment darker than in any other species.
Compsothrips tristis (Cott)
Ant mimic, living at ground level
Imbibing spores of unidentified fungi.