The immature stages of Mesophleps albilinella (Park, 1990) (Lepidoptera: Gelechiidae) are described herein. Host records for this species were unknown until larvae were collected feeding on seeds within seed capsules of downy rose myrtle, Rhodomyrtus tomentosa (Aiton) Hassk. (Myrtaceae) in Hong Kong, China. Collection sites in Hong Kong are superimposed on a country map and are listed in tabular format. A photograph of a containment cage, used for feeding, mating, and oviposition is provided. Images and scanning electron micrographs of the egg and larva are supplemented with chaetotaxal maps, including the pupa. A laboratory culture of M. albilinella facilitated the description of all immature life stages. Though M. albilinella was collected as a potential biological control agent against R. tomentosa in Florida, it was abandoned due to lack of host specificity during initial host range tests.