Marietta leopardina Motschulsky

Hymenoptera: Chalcidoidea: Aphelinidae

Body very small in size (0.5-1.0 mm long), usually pale coloured, with a beautiful pattern of dark bands or spots or both on head, thorax, gaster and legs. Antenna six-segmented in female (antennal formula 1-1-2-1-1) and five-segmented in male (1-1-2-1). Pronotum narrow and transverse, composed of a single plate. Fore wing of almost all known species characteristic and conspicuously maculated with a dark and light pattern of setae; marginal vein long, postmarginal absent, stigmal vein barely visible to punctiform. Mesopleuron large and undivided as in encyrtids. Axillae hardly projecting forwards. Adults commonly collected in association with scales and mealybugs.

The genus can be readily identified by the striking patterns on the body and fore wing.

   Fore wing
   Antenna
 Mesosoma, dorsal view

     
   Adult of M. leopardina - dorsal and lateral views
 Freshly emerged adult of M. leopardina

Species of the genus Marietta are almost always hyperparasitoids of Hemiptera, including Diaspididae, Coccidae and other families. The species are very commonly collected and often erroneously recorded as primary parasitoids. Only Marietta pulchella Howard has been recorded as a primary parasitoid of the scale, Conchaspis angracei Cockerell (Beardsley & Tsuda, 1990). The world fauna of the genus Marietta includes 19 species (Hayat, 1998). Hayat (1986) provided a key to the species, along with host and distribution records.