The little-known larval morphology of two stoneflies of Styloperlidae (Insecta: Plecoptera) in China.

ABSTRACT

The stoneflies are a relatively ancient group of aquatic insects. The larvae of stoneflies are exclusively aquatic and are important bioindicators for water quality changes. However, the identification and classification of stonefly larvae are much more difficult than the adults, due to the lack of sufficient descriptions for most stonefly taxa. Styloperlidae is an endemic stonefly family in South Asia. The larval morphology of this family remains less clear in comparison with their adults. In this paper, the larvae of Styloperla inae Chao, 1947 and Cerconychia flectospina Wu, 1962 are described and illustrated based on specimens from China. Their morphology corresponds with the proposed diagnostic larval characters of Styloperlidae in previous studies. Additional auxiliary characters useful for the identification of larvae in Styloperlidae are discussed. The larvae of S. inae and C. flectospina exhibit subtle morphological differences but can be easily distinguished by the presence or absence of dark sclerites on all the thoracic sternal pits.