Lonomia frankae
Lonomia obliqua
Lonomia rufescens
&_160;others, see text
The genus Lonomia is a moderate-sized group of fairly cryptic saturniid moths from South America, famous not for the adults, but for their amazingly venomous caterpillars, which are responsible for a few deaths each year (e.g., [1]), especially in southern Brazil, and the subject of hundreds of published medical studies.
The caterpillars are themselves extremely cryptic, blending in against the bark of trees, where the larvae commonly aggregate. The larvae, like most hemileucines, are covered with urticating hairs, but these caterpillars possess a uniquely potent anticoagulant venom.
A typical envenomation incident involves a person unknowingly leaning against, placing their hand on, or rubbing their arm against a group of these caterpillars that are gathered on the trunk of a tree. The effects of a dose from multiple caterpillars can be dramatic and severe, including massive internal hemorrhaging, kidney failure, and destruction of blood cells (hemolysis). The resulting medical syndrome is sometimes called Lonomiasis.