Cacomantis is a genus of cuckoo in the family Cuculidae. 

1/ Plaintive cuckoo (Tìm vịt, Cacomantis merulinus)
2/ Banded bay cuckoo or bay-banded cuckoo (Tìm vịt vằn, Cacomantis sonneratii)

The genus name is from the Greek kakos meaning evil or ill-boding and mantis for prophet. 
The name is associated with or supposed to be predicted "rains" as well as ill fortune and bad weather.