Body uniformly brown; including legs and antennal segments; head somewhat darker; fore wing strongly shaded. Head dorsally sculptured, with one pair of long ocellar setae, also one pair of postocular setae well developed. Antennae 8-segmented, III & IV each with transverse sensorium at apex. Pronotum with few lines of sculpture near posterior margin; widest at posterior, with one pair of long posteroangular setae. Meso & metathoracic spinula present. Fore tibia usually with a well-developed tooth. Mesonotum with a long setae arising laterally; metanotum with weak sculpture medially; paired campaniform sensilla present. Fore wing with both rows of setae complete. Tarsi 2-segmented. Abdominal tergites without microtrichia and X with a pair of stout trichobothria. Sternites III–VII with moderately long discal setae; ovipositor weakly developed. Female always macroptera, male wingless.
Male smaller and paler; with a dorsal glandular area on head; fore tibia with a stout tooth, fore femora enlarged and with a basal tubercle.
Intraspecific variation
Not recorded.
Genus and similar species information
Merothrips includes 13 extant species, many of them described from the Neotropics. They all have antennae 8-segmented and the transverse sensoria on segments III & IV are and sometimes slightly inflated. Many species are known only from apterous forms. Merothrips williamsi is characteristic in having the head entirely sculptured and second row of setae on fore wing usually with more than 20 setae. A key to Merothrips species is given by Mound & O’Neill (1974).
World distribution
Described from Paraguay, it is recorded from Brazil, Caribbean, South Africa and USA.
Lives on dead branches, and possibly feeds on fungal hyphae.
Economic importance
Not recorded.
References suggested
Mound LA & O'Neill K (1974) Taxonomy of the Merothripidae, with ecological and phylogenetic considerations (Thysanoptera). Journal of Natural History 8: 481–509.
Mound LA & Marullo R (1996) The Thrips of Central and South America: An Introduction. Memoirs on Entomology, International 6: 1–488.
Published in: 23/12/2016 Posted by: Mariana Lindner
