Simulium ceylonicum

Jitklang, Sanae, Kuvangkadilok, Chaliow, Baimai, Visut, Takaoka, Hiroyuki & Adler, Peter H., 2008, Cytogenetics and morphotaxonomy of the Simulium (Gomphostilbia) ceylonicum species group (Diptera: Simuliidae) in Thailand, Zootaxa 1917, pp. 1-28 : 23

Key to larvae of 10 cytoforms in the S. ceylonicum group in Thailand *

( Figs. 9–10 )

1 Postgenal cleft ( Fig. 9 E–G)> 5.0 x as long as postgenal bridge, reaching or approaching hypostoma.....2

- Postgenal cleft ( Fig. 9 A–D, H–J) <5.0 x as long as postgenal bridge, leaving moderate length of postge- nal bridge.....................................................................................................................................................4

2 Abdomen without reddish-brown markings dorsally; abdominal setae unbranched ( Fig. 10 A)................... ................................................................................................................................................. nr. asakoae 4

- Abdomen with reddish-brown markings dorsally; abdominal setae branched ( Fig. 10 B)..........................3

3 Abdomen yellowish ............................................................................................................. trangense n. sp.

- Abdomen yellowish except segments I–IV greenish ......................................................................... sheilae

4 Abdomen yellowish except segments I and IV greenish.............................................................................5

- Abdomen yellowish except segments I–III or I–IV greenish......................................................................6

5 Postgenal cleft ( Fig. 9 J) subequal to or shorter than postgenal bridge. ................................... inthanonense

- Postgenal cleft about twice as long as postgenal bridge ( Fig. 9 D).......................................... nr. asakoae 3

6 Abdomen yellowish except segments I–III greenish...................................................................................7

- Abdomen yellowish except segments I–IV greenish...................................................................................8

7 Abdominal segment V with reddish-brown transverse band dorsally ................................... curtatum n. sp.

- Abdominal segment V without distinct colored band ............................................................. nr. asakoae 2

8 Head spots faint ......................................................................................................................... nr. sheilae 3

- Head spots distinct.......................................................................................................................................9

9 Hypostoma shorter than its greatest width ....................................................................................... asakoae

- Hypostoma nearly as long as its greatest width ............................................................... doisaketense n. sp.

Figures

FIGURE 9. Postgenal clefts of larvae of 10 cytoforms of the Simulium ceylonicum species group in Thailand. (A) S. asakoae, (B) S. curtatum n. sp., (C) S. nr. asakoae 2, (D) S. nr. asakoae 3, (E) S. nr. asakoae 4, (F) S. sheilae, (G) S. trangense n. sp., (H) S. doisaketense n. sp., (I) S. nr. sheilae 3, and (J) S. inthanonense. Scale bar = 0.1 mm.

FIGURE 10. Two types of abdominal setae of larvae in the Simulium ceylonicum species group in Thailand. (A) unbranched setae, (B) branched setae. Scale bar = 0.01 mm.