Freshwater Macroinvertebrates in Hong Kong

Labiobaetis diffundus

General appearance
Body size small medium up to about 5mm long (excluding antennae & cerci)
Body cylinderical & elongated, frontal ridge on head between antennae

Head
Antennal scape with a distinct lobe at distolateral margin
Terminal segment of maxillary palpus with a distinct concave near apex
The details for mouthparts illustrated in the following pictures

Thorax
Hindwing pad absent
No villiopore on femora
Legs pale without marking
The details for each leg illustrated in the following pictures

Abdomen
6 pairs of gills II - VII, single, tracheated but poorly seen
Central filament is not reduced -- 3 caudal filaments are shown clearly; cerci length is slightly longer than half of body length

Legs

Its mouthparts of labrum, mandibles, maxillae and labium are illustrated as follow (hypopharynx is excluded).

Labrum

Maxillae

Mandibles

Labium

Distribution:
In Hong Kong, specimens are recorded from Shing Mun, Tai Po Kau Forest Stream, Hatton Road (nr. University of Hong Kong).