The quantitative determination of selected dyestuff components by high performance liquid chromatography, diode-array detection, and post-run data manipulation was used to recognize dyes on historic yarns prepared from <i>Dactylopius coccus</i> (American cochineal), <i>Kermococcus vermilio</i> (kermes), <i>Porphyrophora polonica</i> (Polish cochineal), <i>Porphyrophora hamelii</i> (Ararat cochineal), or <i>Kerria lacca</i> (Indian lac). Study of scale-insect red dyes suggests a rather widespread use of mixed primary sources, not only of insect reds alone, but also in combination with plant reds and tannins.