Abstract
Two new species of Larsia Fittkau, 1962 are described and figured as male, pupa and larva. Diagnosis to male of this genus is emended. An annotated checklist of the world's valid Larsia species is given and keys to pupae and larvae of known species inthe Neotropical region are provided. Non-biting midges of the genus Larsia are small to minute dipterans with worldwide distribution, often found in ponds and the littoral zone of lakes. The genus belonging to Pentaneurini tribe was erected by Fittkau (1962) with Ablabesmyia atrocincta Goetghebuer (1942) as the type species. Prior to the present study Larsia comprised 18 described valid species (Table 1). The adult males are distinguished by the following combination of characters: presence of scutal tubercle, lyrate or comb-like tibial spurs in all legs and r-m and m-cu confluent (Murray & Fittkau 1989). Whereas, the thoracic horn with alveolar respiratory atrium is the diagnostic character for the pupae (Fittkau & Murray 1986). The larvae can be distinguished by having antenna 3.5 times length of mandible, with ring organ of basal segment near middle and inner apical margin of dorsomentum directed medially (Epler 2001).
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