Three genera are recognised in this family, Heratythrips and Oligothrips from California, each containing a single species (Mound & Marullo 1999), and Holarthrothrips from the Old World between India and the Mediterranean. The four species described in this genus are all associated with the flowers of date palms (Phoenix dactylifera). The adults of all six species of Adiheterothripidae have a curious conical sensorium on antennal segments III and IV, a character state that is found otherwise only in a few fossil Thysanoptera.

Holarthrothrips indicus Bhatti & Ananthakrishnan

Available names: Original name Holarthrothrips indicus Bhatti & Ananthakrishnan, 1978.

Biology: Known only from the inflorescences of Phoenix dactylifera, the date palm, but nothing is known of the biology of the species.

Distribution: India and Bangladesh.

Recognition: Body brown to light brown, legs yellow with femora tinged with brown; antennae brown with segments III-IV yellow; forewing uniformly pale. Head without long setae, eyes not prolonged ventrally. Antennae 9-segmented, segments all clearly distinct from each other and bearing rings of weak microtrichia, VIII long and slender; segments III and IV each with one conical sensorium externally at apex. Pronotum with 2 or 3 pairs of posteroangular setae that are twice length of discal setae. Tarsi 2-segmented; fore tarsi with stout recurved hamus that meets a stout seta at its tip. Mesonotum with one pair of setae medially. Metanotum with concentric rings of sculpture lines bearing microtrichia; median setae close to posterior margin. Forewing slender with apex almost acute; only one cross vein well-developed; basal stem of second longitudinal vein with 3 setae; costal margin with long cilia as well as setae. Tergites II-VI with marginal comb of microtrichia laterally, VII-VIII with comb complete across median area; lateral areas of tergites with many rows of microtrichia; pleurotergal sutures weakly developed. Median sternites with 4 pairs of marginal setae. Male with two pairs of stout setae posterolaterally on segment IX.

Related species: Four species are recognised in the genus Holarthrothrips, distributed between India and the Mediterranean (Bhatti 1986). Curiously, all four species apparently live only in the inflorescences of Phoenix dactylifera, the Date Palm. In H. tenuicornis from the Mediterranean, and also H. jambudvipae from southern India, the apical half of the forewings is shaded, and the abdominal sternites lack discal setae. In contrast, in H. josephi from Iraq and Oman, and also in H. indicus , the forewings are pale, and the abdominal sternites bear discal setae laterally. In H. josephi, abdominal tergites II-VI bear a complete posteromarginal comb of microtrichia, whereas this comb is absent medially on these tergites in H. indicus.

Generic relationships: Holarthrothrips is placed in the family Adiheterothripidae, together with two monobasic genera from western North America (Mound & Marullo 1999).



Holarthrothrips josephi

Antennal segments II-VI