This species has not been studied by the present authors, and is known only from the original description.
Judging from the original description, H. irretius has unusually short setae on the anterior and lateral margins of the pronotum. Over 100 species are listed in the genus Hoplandrothrips, of which more than 20 are described from North America, including five from California. Cott (1956) provided a key to four of the species recorded from California, Stannard (1968) a key to seven species from Illinois, and Mound & Marullo (1996) a key to 18 Neotropical species. Species concepts within this, and several other, genera of fungus-feeding thrips remain unclear, due to structural variation involving allometric growth patterns in one or both sexes.
Hoplandrothrips irretius Kono
Presumably feeding and breeding on fungi on dead branches
Described from eight females and eight males taken "on nursery stock from Mission, Texas".