part of larval gnathal appendages larval labium TGMA:0000882 TGMA:0000882 The fused third or posterior pair of gnathal appendages; divided into a distal prelabium, comprised of the prementum, ligula and labial palpi, and a proximal postlabium (postmentum) which may be subdivided by a transverse suture into a distal mentum and a proximal submentum. In mosquito larvae, the proximal limit of the labium is the imaginary pregular suture, its lateral margin is arbitrarily taken as the hypostomal suture and its anterior limit is an imaginary transverse line behind the salivary orifice. default_namespace