LAUSR

Abstract Bittacidae is the only cosmopolitan family in Mecoptera and little information is available on the larval morphology in most genera. Here, we investigate the morphology of the first-instar larva of the two-tailed hanging-fly Bicaubittacus longiprocessus (Huang & Hua, 2005) using light and scanning electron microscopy. The larva is eruciform and possesses three pairs of thoracic legs and eight pairs of abdominal prolegs. The head bears a median ocellus on the frons and a pair of compound eyes with seven ommatidia on the lateral sides of the head. The distal segment of the maxillary palp possesses 11 sensilla basiconica on the apex. Dorsal protuberances bear slender dorsal setae, and are likely adapted to the soil-spraying behavior of the larva for holding soil packs. These morphological features can take a significant part in larval taxonomy in Bittacidae.