Chaetonerius Hendel, 1903

Sepúlveda, Tatiana A. & Souza, Diego De S., 2019, A new species of Chaetonerius Hendel (Diptera: Neriidae) from Northeast Madagascar, Zootaxa 4656 (2), pp. 389-392 : 389-390

Key for the identification of Chaetonerius Hendel from the East African islands (adapted from Sepúlveda & de Carvalho, 2019)

1 Occiput lateral and postgena in a right angle on meeting point with occiput posterior. Face blackish-brown. Proepisternum inflated. Fore coxa mostly brown. Palpus brown............................ C. kirkspriggsi Sepúlveda & de Carvalho

- Occiput lateral and postgena curved on meeting point with occiput posterior. Face partially to completely yellow. Proepister- num flattened. Fore coxa yellow. Palpus at least partially yellow............................................... 2

2. Underdeveloped antennal base present. Thoracic median brown stripe not divided by yellow stripe, narrowing to scutoscutellar suture. Dorsocentral yellow stripe narrow (width about one fifth of brown median stripe), converging at the scutoscutellar suture.............................................................................................. 3

- Underdeveloped antennal base absent. Thoracic median brown stripe divided medially by a yellow stripe. Dorsocentral yellow stripe wide (width about half of median brown stripe)........................................................ 4

3 Abdomen brown in males and brown with one median longitudinal yellow stripe in females. Three well-developed fronto-orbital setae............................................................... C. ebejeri Sepúlveda & de Carvalho

- Abdomen brown with two longitudinal yellow stripes. Four well-developed fronto-orbital setae.......... C. serratus sp. n.

4 Mid and hind coxae yellow. Face dark yellow with median sagittal brownish-yellow to blackish-brown stripe. Katepisternum brown ventrally with dorsal half paler to completely yellow................................. C. alluaudi (Giglio-Tos)

- Mid and/or hind coxae brown. Face dark yellow with no sagittal blackish-brown stripe, at most with a median darkening, not contrasting. Katepisternum completely brown.............................................................. 5

5 Thorax dorsally with one median brown V-shaped stripe. Mid and hind coxae brown. Cercus parallel sided with rounded apex, which has very long and thick setae resembling claws...................... C. madagasikara Sepúlveda & de Carvalho

- Thorax dorsally with V-shaped brown stripe partially divided medially by one gray pruinose narrow stripe; in some cases, the brown stripe fades posteriorly. Mid coxa partially to completely brown and hind coxa yellow. Cercus narrowing distally with slightly pointed apex and sparse, thin and short setae............................. C. kotrbae Sepúlveda & de Carvalho