Diopsis indica 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 : 44-46

Diopsis indica Westwood, 1837

( Figs 1, 9)

Diopsis indica Westwood, 1837: 299 (no formal type series, Westwood only based himself on “figures and meagre description” by Donovan of specimens from Bengal): Donovan 1800–1804: pl. 58 and text on next 2 pages; Brunetti 1913: 185 (in part); Datta & Biswas 1985: 220 (in part?).

Diopsis assimilis Westwood, 1837: 300 , n. syn. (2 ♀ “ syntypes ” in poor condition, origin not given, identified as “cotypes” by E.E. Austen, 5.xi.1907 (BMNH). The specimen with the head is now designated as the lectotype and the other one as paralectotype): Steyskal 1972: 7; Feijen 1978: 11; Feijen & Feijen 2009: 703.

Not Diopsis assimilis Lindner, 1962: 11 (this is a West African species): Steyskal 1972: 7; Feijen 1978: 11.

Diopsis? indica Westwood : Howlett 1909: pl. 67-7; Brunetti 1913: 184; Curran 1936: 2; Vazirani & Rathore 1976: 67; Sharma 1988: 143; Datta & Parui 1999: 30; Parui et al. 2006: 101; Mitra & Bhattacharya 2010: 394.

Not Diopsis westwoodii Westwood, 1848 : pl. 18, fig. 1 (no formal type series, origin from Java. Description on explanation to plate. Westwood referred to “ Diopsis westwoodii De Haan ” in a manuscript. This is a valid species, while Westwood as author’s name is the established procedure in this case.): Van der Wulp 1897: 187; Brunetti 1907: 165; Steyskal 1977: 33.

Not Diopsis graminicola Doleschall, 1857: 417 . Replacement name for Diopsis apicalis Doleschall, 1856: 413 (no surviving type specimens known, origin from Java; this is a valid species): Van der Wulp 1897: 187; Brunetti 1907: 165; Steyskal 1977: 33.

Not Diopsis indica auct.: Macquart 1848: 226 (Java species); Van der Wulp 1896: 171, 1897: 187 (Java species, incl. D. westwoodii and D. graminicola ); Meijere 1916: 89, 1917: 328, 1919: 31 (all Sumatra); Frey 1934: 335 (Java record); Chen 1949: 2 (Chinese species, probably Diopsis chinica Yang & Chen, 1998: 468 , 477); Steyskal 1972: 9, 1977: 33.

Distribution: India, maybe Bangladesh. Records in other countries are based on misidentifications. Steyskal (1972) erroneously included in distribution “ East Pakistan to southern China, south to Java”. Vazirani and Rathore (1976) assumed that “ D. indica is confined to the hilly tracts.”

Remarks: Westwood (1837) based his description only on Donovan’s (1800–1804) illustration and remarks: “Black; head, anterior part of the abdomen, and legs ferruginous; two spines on the posterior extremity of the thorax.” The illustrations of Donovan and Westwood have now been combined ( Fig. 1). Donovan also stated: “Our own specimens (and they are most assuredly the Diopsis Ichneumonea of Linnaeus) were brought from Bengal, where it was discovered by Mr. Fichtel”. Westwood referred to the type locality as “Habitat in Bengaliâ. D. Fichtel.” The collector was Leopold von Fichtel (1770–1810). Rögl (1982) stated that “von Fichtel … became famous for his collections of objects of nature and his worldwide travels bringing him even to India.” According to Kázmér and Vávra (2002), Fichtel “was a member of the .... Asiatic Society of Bengal in Calcutta.” Steyskal (1972) gave as origin of the type “Bengal (= East Pakistan)”, but Steyskal (1977) reverted to “Type-loc: Bengal.” Bengal is nowadays divided between Bangladesh and the Indian territories of West Bengal, Tripura and the Barak Valley of Assam. Given that Fichtel was a member of the Calcutta Society and collected and described Foraminifera of the east coast of India, it seems most likely that India is the origin of D. indica and not Bangladesh. A further indication is that D. indica and species nr D. indica are quite common in West Bengal, while we have not yet seen specimens from Bangladesh.

Like for D. abdominalis, Westwood gave no type origin for his D. assimilis . However, as it was argued for D. abdominalis the combination of characters places D. assimilis in the D. indica species-group with India as the most likely place of origin. Contrary to D. abdominalis , the type series of D. assimilis consists of two females housed in BMNH. The condition of these two syntypes is poor: one has no head and the other is a bit teneral. The following important character states can be mentioned: collar glossy brown, but pollinose laterally, scutum and scutellum dark brown, pollinose, round apical wing spot, incrassate front femur, strong facial teeth and brown abdomen with darker apex. Westwood’s description of D. assimilis is somewhat superficial, but he also illustrated ( Westwood 1837, figs 7, 8) both specimens, while wondering whether they were ♀ and ♂. Both figures show the characteristic black tip of the abdomen as does Westwood’s description: illo rufescenti-fulvo, apicem versus saturatius fusco. This agrees well with the D. indica abdomen ( Figs 1, 9). To all extent, there are no differences in the descriptions of D. indica and D. assimilis and the latter species is now considered as a junior synonym of D. indica . It should be pointed out that Westwood did not see D. indica specimens that he described. If he would have seen them, it is unlikely that he described D. assimilis . The same happened with other species described by Westwood for which he had no access to earlier described species: D. thoracica became a junior synonym of D. longicornis Macquart , while Diopsis tenuipes Westwood became a junior synonym of Diopsis apicalis Dalman.

In 1837, Westwood amended his description of D. indica , a brief description of a variety from Java: Var. Insectum Javanicum in musaeo Dom. Hope à cel. De Haanio communicatum (sub nomine D. apicalis, Wied. ) staturâ et magnitudine D. indicae benè convenit. However, in 1848 Westwood described and illustrated this specimen as “ Diopsis westwoodii . De Haan.” with the following remark: “Inhabits the Island of Java. Communicated by M. De Haan, with the MS. name adopted above.” Westwood’s very nice illustration (pl. 18, fig. 1) shows an unmistakable Java species that is very different from D. indica . This large and elongate species with a vague almost preapical wing spot is quite common on Java and is, in fact, the most aberrant species in the D. indica species-group. A closely related species occurs in Sumatra. In 1856, Doleschall described and illustrated another species from Java and named it Diopsis apicalis . As this name was preoccupied by Dalman (1817), Doleschall (1857) gave the species as replacement name Diopsis graminicola . His description and illustration are rather poor, but sufficient to distinguish the species as very different from D. westwoodii . Next to D. westwoodii and D. graminicola at least one more species of the D. indica species-group is now known to occur in Java. Van der Wulp (1897), based on cursory inspection, placed both D. westwoodii and D. graminicola as junior synonyms of D. indica . Van der Wulp gave a nice illustration (pl. 8, fig. 2) of what he considered D. indica , but this is an unmistakable D. westwoodii with its elongate body shape and colour pattern. The synonymies proposed by Van der Wulp were accepted by Brunetti (1907) and Steyskal (1972, 1977). However, both synonymies are now rejected, and both species are considered as valid species from Java.