Tisamenus lachesis is a stick insect species (Phasmatodea), in the family of the Heteropterygidae endemic to the Philippine Polillo Island.
Only males of this Tisamenus species are known so far. These reach a length of 51mm and are rather elongated and long-legged. Like Tisamenus draconina and Tisamenus hystrix, the species is relatively spiny. As with these, there are distinct, relatively sharp spines on the posterior mesonotum (posterior mesonatals) and smaller, blunter ones in the middle of the metanotum (median metanotals). The triangle on the mesonotum typical of the genus is significantly longer than it is wide at the front in Tisamenus lachesis, while it is as wide as it is long in Tisamenus hystrix. In both species the anterior corners of the triangle end in single spines, while in Tisamenus draconina they end in compound spines. The segments two to five of the abdomen are occupied in the posterior area with pointed pairs of lateral spines. The median spines that are also present there are much smaller and hardly recognizable.
James Abram Garfield Rehn and his son John William Holman Rehn described the species in 1939 as Hoploclonia lachesis. The description is based on a male holotype which was collected on Polillo Island and came from the collection of Taylor. It is deposited in the National Museum of Natural History in Washington, D.C. Rehn and Rehn divided the Philippine representatives they led or described into Hoploclonia according to morphological aspects into different groups. They placed Hoploclonia lachesis in the so-called Draconina group together with Hoploclonia draconina (today Tisamenus draconina) and the newly described Hoploclonia hystrix (today Tisamenus hystrix), very strongly spined, rather elongated and long-legged species. Until 2004 Tisamenus lachesis was included in Hoploclonia. Only Oliver Zompro placed the species in the genus Tisamenus together with all other Philippine representatives of Hoploclonia. In October 2000 Zompro discovered in the collection of the Natural History Museum in London a male collected in 1908 by C. S. Banks in the Philippines which was a Juvenile (organism) male specimen and was labeled as Obrimus species. His determination of the animal showed that it could be another representative of this species, so that he, following the genus at the time, named it Hoploclonia cf. lachesis . It resembles the adult holotype in many features, but is significantly less spined than this, especially at the edges of the meso- and metanotum.