Morphology: Early passages consisted of attached cells and vesicles in suspension, whereas later passages consisted primarily of attached, spherical cells; Growth characteristics: doubling time is 155.2 hr; Karyology: variable ploidy, ranging from 20 chromosomes/cell (diploid) to above 30 chromosomes/cell. Unique properties: cells withstood incubation at 40°C for 1 h with no decrease in viability, which was accompanied by increased levels of one heat shock protein (43 kDa) and of the hsp68a transcript; a transcriptome of this cell line is available; this line is sensitive to RNAi; functional TcA-specific promoters have been developed for this line; Authentication: DNA fingerprinting (DAF-PCR) results confirmed identity and amplification of genomic DNA with species-specific primers yielded DNA fragments of the expected sizes and with sequences identical to those from the published Tribolium genome.