LAUSR

Abstract A new and a known species of the genus Mesorhabditis (Osche 1952) Dougherty, 1953 are described and illustrated based on light and scanning electron microscopic observations. The known species M. microbursaris (Steiner 1926) was isolated from the larva of ground beetle (Phyllophaga sp.) and the new species M. denticulatus from the larva of longhorn beetle (Cerambycidae), emerging inside the dead log of Dulbergia sisso. The new species M. denticulatus is characterised by lateral fields with six incisors. Lips with raised setose sensilla. Cheilostom angular bracket-shaped. Metastegostomal swellings with two prominent denticles. Pharyngeal collar indistinguishable. Phasmid posterior to anus. Spicules 1.2–1.6 times anal body diameter long with round capitula, short and narrower calomus. Gubernaculum 50% of spicule length. Bursa rudimentary. GP five pairs, one pair precloacal and four pairs post cloacal, arranged in 1/1 + 1 + 2 configuration. GP4 and GP5 closely placed forming a group. The association between the species of the genus Mesorhabditis and insects is discussed.