Dacus Fabricius 1805
Creators: name: Abhishek, Venkateshaiah
name: David, Karamankodu Jacob
name: Hancock, David Lawrence
name: Pradeep, Shivanand
name: Kalleshwaraswamy, C. M.
name: Sridhara, S.
name: Satish, K. M.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Tephritidae
Dacus

description: Genus Dacus Fabricius
Dacus Fabricius, 1805: 272.— Drew, 1989: 16. Type species: Dacus armatus Fabricius, 1805, by subsequent designation of Speiser, 1924: 140.
Diagnosis
Genus Dacus can be differentiated from all other genera of Dacini by the fused abdominal tergites I– V, with only tergites I and II fused in the other genera. Other characters, such as the patterned praeputium on the glans (absent in D. persicus), also occur outside the genus.
Illustrated key to species of Dacus known from the Indian Subcontinent
Modified after David et al. (2020). Includes species known from India, Bangladesh, Bhutan, Nepal, Pakistan and Sri Lanka. A record of D. trimacula (Wang) from Nepal (Leblanc et al., 2019) is a misidentification of Dacus fletcheri Drew. Distributions are noted for species not recorded from mainland India. Subgeneric placements follow Hancock and Drew (2006) and Drew and Romig (2013).
1. Wing with faint costal band expanded into a broad apical patch that includes most of cell m (Fig. 43); abdomen without a black medial vitta on tergites II–IV (Fig. 35)....................................... D. (Neodacus) sphaeroidalis (Bezzi)
- Wing with apical patch smaller, if broadly rounded and entering cell m anteriorly then abdomen with a broad black medial vitta on tergites II–IV...................................................................................... 2
2. Combined length of antennal segments shorter than height of head; costal cells bc and c colourless Fig. 36, 42); if scutum black then either a postsutural medial yellow scutal vitta present or costal band narrow and interrupted subapically (Fig. 40); abdomen with tergite I (basal part of combined syntergite I+II) distinctly broader than long (as on Fig. 32)...................... 3
- Combined length of antennal segments longer than height of head; costal cells bc and c often fuscous, if colourless then scutum black, postsutural medial yellow scutal vitta absent and costal band not interrupted subapically (Figs 36–39, 41–45); abdomen with tergite I (basal part of combined syntergite I+II) quadrate or petiolate (as on Fig. 31)........................... 5
3. Scutum black with a postsutural medial yellow vitta (Fig. 14), costal band pale and indistinct (Fig. 40); male without a pecten of cilia on tergite III; female with oviscape much longer than tergite V and bulbous. (Fig. 32).................................................................................................. D. (Leptoxyda) persicus Hendel
- Scutum reddish brown to black without a postsutural medial yellow vitta, costal band narrow but fuscous and distinct; male with a pecten of cilia on posterolateral margin of tergite III; female with oviscape much shorter than tergite V and dorsoventrally flattened............................................................................................ 4
4. Scutum black with red-brown markings; costal band interrupted subapically; abdomen largely black and with a medial black vitta [Sri Lanka] (Drew and Romig 2013: fig. 375).................................. D. (Didacus) keiseri (Hering)
- Scutum reddish brown (Fig. 10); costal band not interrupted subapically (Fig. 36); abdomen red-brown with at most a pair of submedial fuscous spots on tergite III (Fig. 28)....................................... D. (Didacus) ciliatus Loew
5. Wing with pale anal streak in cell cup extension (Fig. 39); scutum (Fig. 13) and abdomen red-brown without black abdominal medial vitta (Fig. 31); breeds on plants belonging to Cucurbitaceae ............ D. (Callantra) longicornis (Wiedemann)
- Wing without anal streak; scutum and abdomen red-brown to black with or without black abdominal medial vitta; breeds on plants belonging to Asclepiadaceae ....................................................................... 6
6. Costal cells bc and c fuscous (Figs 38, 39, 41, 44, 45); scutum red-brown or mostly black (as on Figs 10, 16); face largely black or fulvous to fuscous with black spots either separate or united to form an inverted U-shaped pattern................... 7
- Costal cells bc and c colourless (Figs 36, 40, 42); scutum black (Fig. 16), face largely black or with two large black spots connected by a broad band above oral margin............................................................. 18
7. Scutum with medial and lateral postsutural yellow vittae (Drew and Romig 2013: fig. 393)................................................................................................ D. (Mellesis) icariiformis (Enderlein)
- Scutum without lateral postsutural yellow vittae, medial vitta present or absent.................................... 8
8. Medial postsutural yellow vitta often present (Fig. 11); wing with a broad costal band confluent with vein R 4+5, expanded into a large apical spot that enters cell m (Fig. 37)....................................... D. (M.) discophorus (Hering)
- Medial postsutural yellow vitta absent; wing with a broad costal band overlapping vein R 4+5, often expanded slightly towards apex but not entering cell m............................................................................ 9
9. Fore femur with 2–3 subapical ventral black spines (Fig. 24); costal band with apical patch distinctly darker than remainder (Fig. 41); abdomen strongly petiolate, tergite I about twice as long as wide (Fig. 33); postsutural supra-alar seta absent............................................................................ D. (M.) polistiformis (Senior-White)
- Fore femur without subapical spines; costal band with apical patch not distinctly darker than remainder; abdomen often not strongly petiolate; postsutural supra-alar seta usually present................................................. 10
10. Postpronotal lobe yellow to reddish brown; scutum reddish brown, with or without fuscous markings................. 11
- Postpronotal lobe dark fuscous to black; scutum black with or without red-brown patches posteriorly................. 15
11. Wing cell br entirely hyaline in basal three-quarters beyond level of dm-cu crossvein; abdomen with a narrow medial black vitta on tergites III– V [Bhutan, Nepal] (Drew and Romig 2013: fig. 390)............................ D. (M.) feijeni White
- Wing cell br fuscous in at least anterior half; abdomen without a narrow medial black vitta......................... 12
12. Abdomen with tergite I quadrate (David et al., 2020. fig.12); cell br almost entirely fuscous (Fig. 45)...................................................................................... D. (M.) viraktamathi David & Hancock
- Abdomen petiolate with tergite I distinctly longer than broad; cell br fuscous only on anterior half.................... 13 13. Postpronotal lobe yellow; scutum and abdomen without fuscous markings; anatergite almost entirely yellow [Andaman Is] (Drew and Romig 2013: fig. 396)........................................... D. (M.) insulosus Drew & Hancock
- Postpronotal lobe dark brown or reddish brown; scutum and abdomen with fuscous markings; anatergite yellow at most on ventral quarter...................................................................................... 14
14. Postpronotal lobe dark fulvous; anatergite dark fulvous with ventral quarter yellow; scutellum with a narrow dark basal band; fore, mid and most of hind femora orange-brown [Sri Lanka]............... D. (M.) ancoralis Leblanc & Doorenweerd
- Postpronotal lobe reddish brown (Fig. 12); anatergite entirely dark brown (Fig. 21); scutellum with a broad dark basal band (Fig. 12); all femora fuscous with orange-brown apices (Fig. 21)...................... D. (M.) jacobi David & Sachin
15. Thorax with notopleura black (Drew and Romig 2013: fig. 417)................ D. (M.) vijaysegarani Drew & Hancock
- Thorax with notopleura yellow......................................................................... 16
16. Wing cell br entirely fuscous or almost so; abdominal tergites II and III with large posteromedial orange-brown patches and tergites II–IV dorsally humped (Maneesh et al. 2022: fig. 4)................................. D. (M.) fletcheri Drew
- Wing cell br fuscous only in anterior half; abdominal tergites II and III without large posteromedial orange-brown patches and tergites II–IV not dorsally humped...................................................................... 17
17. Abdomen petiolate with tergite I distinctly longer than broad and tergites III–IV entirely black [Bhutan] (Drew and Romig 2013: fig. 411).......................................................... D. (M.) siamensis Drew & Hancock
- Abdomen with tergite I quadrate and tergites III–IV with large posteromedial patches [Bhutan] (Drew and Romig 2013: fig. 388)....................................................................... D. (M.) dorjii Drew & Romig
18. Wing with a broad costal band that expands over r-m crossvein (Fig. 42), anepisternal stripe broad (Fig. 25), reaching postpronotal lobe......................................................... D. (M.) ramanii Drew & Hancock
- Wing with broad costal band confluent with vein R 4+5, overlapping towards apex but without an extension over r-m crossvein; anepisternal stripe narrow, barely wider than notopleural lobe................................................. 19
19. Anatergite partly yellow/partially black.................................................................. 20
- Anatergite wholly black............................................................................... 21
20. Postpronotal lobes, transverse suture, scutellum and anepisternal stripe are completely orange red (Figs 46, 47); 0.80 of hind femur black (Fig. 47); narrow transverse suture (0.15 mm) (Fig. 49)................................................................................................ D. (M.) nagarathnae Abhishek, David & Hancock, sp. nov.
- Postpronotal lobes, transverse suture, scutellum and anepisternal stripe are completely yellow (Figs 77, 78), 0.6 black hind femur; broad transverse suture (0.22 mm) (Fig. 77).................................... D. (M.) maculipterus White
21. Scutellum with broad basal band (0.16 mm) (Fig. 59); abdomen wholly black (Fig. 61); lateral surstylus fuscous (Figs 63, 64), phallus elongate (3. 76 mm), anterior lobe of surstyli pointed (Fig. 63)..... D. (M.) venkateshi Abhishek & David, sp. nov.
- Scutellum with narrow basal band (0.09 mm) (Fig. 69); abdomen with tergite III–IV with medial brown patches (Fig. 71); lateral surstylus fulvous/ yellow (Figs 73, 74); phallus short (1. 5mm), anterior lobe of surstyli blunt (Fig. 73)...................................................................................... D. (M.) crabroniformis (Bezzi)
description: Published as part of Abhishek, Venkateshaiah, David, Karamankodu Jacob, Hancock, David Lawrence, Pradeep, Shivanand, Kalleshwaraswamy, C. M., Sridhara, S. & Satish, K. M., 2024, New Indian species of Dacus Fabricius (Diptera: Tephritidae: Dacinae: Dacini) similar to Dacus crabroniformis (Bezzi), endemic to the Western Ghats and Northeastern Himalayas, pp. 366-382 in Zootaxa 5446 (3) on pages 369-373, DOI: 10.11646/zootaxa.5446.3.3, http://zenodo.org/record/11101875