Dacus (Neodacus) Perkins 1805

Subgenus Neodacus Perkins Neodacus Perkins, 1937: 58. Type species Neodacus newmani Perkins, 1937, by original designation. Diagnosis: Antennae not or only slightly longer than vertical height of head, the first segment shorter than or almost as long as second segment; supra-alar seta present or absent, abdomen not strongly petiolate or club shaped and sternite V with posterior margin straight or weakly concave. Host plants Asclepiadaceae. Comments: Genus Dacus is well distributed in the Asian region and species of subgenera Mellesis Bezzi, Callantra Walker and Neodacus are best known for mimicking wasps. Subgenus Neodacus is currently only known from one species in India, i.e. D. sphaeroidalis (Bezzi); however, many species appear similar to each other due to shared characters such as a faint costal band with a broad apical spot, as in D. santongae Drew & Hancock and D. sphaeroidalis that, along with diversity in genitalic characters (Hancock and Drew, 2006), makes possible the presence of cryptic species. We encountered many specimens of Dacus similar to D. sphaeroidalis throughout the Himalayan region including the eastern Himalayas, with perhaps a detailed morphological as well as genetic analysis required to solve this mystery. As a result, a new species of subgenus Neodacus is described here. Transverse and longitudinal bands on abdominal tergites are key characters diagnosing many species of subgenus Neodacus and here we found distinct difference in the bands on abdominal tergites, especially on tergite V. Hancock and Drew (2006, 2024) defined seven groups of Asian and Australasian Neodacus and the two species described here belong to the sphaeroidalis group; however, Dacus sp. in this manuscript differs in possessing a longer posterior lobe of the lateral surstylus as seen in the absonifacies group.