Diopsis abdominalis Westwood, 1837

Feijen, Hans R., Feijen, Cobi & O., P., 2019, An annotated catalogue of the stalk-eyed flies (Diopsidae: Diptera) of India with description of new species in Megalabops Frey and Teleopsis Rondani, Israel Journal of Entomology (Oxford, England) 49 (2), pp. 35-72 : 43

Diopsis abdominalis Westwood, 1837

( Fig. 8) Diopsis abdominalis Westwood, 1837: 301 (holotype by monotypy, apparently lost, type locality unknown): Steyskal 1972: 7, 1977: 36 (as “dubious species”); Feijen 1978: 11, 1989:

61; Feijen & Feijen 2009: 703.

Distribution: Most likely India.

Remarks: Westwood did not indicate the origin of his single specimen and doubted whether it was not conspecific with his D. assimilis . In the description, he mainly indicated a few differences from D. assimilis . Main differential characters were the glossy black abdomen [ejus nihilominus totum castaneo-nigrum est et nitidum], the almost glossy collar [collare et scutellum nigra subnitida], the black scutellar spines [spinae scutellares et metathoracicae piceo-nigrae] and (in the D. assimilis description) the pollinose scutum [niger, obscurus, haud nitidus, cinerascentisericeus]. Feijen and Feijen (2009) already indicated that from the combination of characters given by Westwood it appears quite certain that D. abdominalis belongs to the D. indica species-group. The combination of pollinose scutum, black scutellar spines and blackish abdomen confidently points in that direction. In 1907, Austen identified specimens in BMNH as belonging to D. abdominalis . They originated from India, Myanmar and Thailand.At least the Indian specimens (ex coll. Bowring) conform well with Westwood’s original description in, for example, glossy collar, pollinose scutum and scutellum, small apical wing spot and almost black abdomen. In India, several species of the D. indica species-group with blackish abdomens occur. Of the flies now examined, specimens from Karnataka with their black scutellar spines appear to conform best ( Fig. 8) and will, at a later stage, be redescribed, with designation of a neotype. As far as the colour of the dorsal abdomen in Indian Diopsis is concerned, care has to be taken in its use as a differential character as some intraspecific variation does occur. Larger series have to be studied, while the study of genitalia and DNA analyses are paramount.