SCARLET (תּוֹלָע, H9355, תּוֹלֵעָה, H9357, שָׁנִי, H9106, כַּרְמִיל, H4147). The dye used for coloring the wool and thread a scarlet color undoubtedly came from the insect, Coccus ilicis. This is an insect pest which attacks the species of oak called Quercus coccifera, commonly called the kermes oak. The insect has sometimes been called the kermes bug. The oak is evergreen, never grows taller than twenty ft., and is of a dense sturdy habit. The acorns are borne in ones or twos, about one inch long, and they are half enclosed in a spiny cup.
The insect which produces the dye is a scale which soon covers the young branches, if not controlled. These scales produce a white fluff similar to cotton wool, similar to the American blight (wooly aphis) and to the insect which attacks the cacti known as prickly pear—the cochineal, from which the red culinary coloring comes.
Actually, although the name “scarlet” is used, the shade of color produced by this insect is far more crimson. It is believed that the actual preparation of the dyes was done by the Phoenicians, though it is agreed that the Egyptians taught the Israelites the actual application.
It is obvious that this scarlet dye was known as far back as 1700 b.c., for the midwife put a scarlet thread around the hand of Zerah in order to make sure that he was known as the first-born.
It is interesting to note that the Arabs call Coccus ilicis, “kermex,” which is similar to the Eng. word kermes and to the Heb. word karmîl. In Jeremiah 4:30, shānî is tr. “crimson” and in Isaiah 1:18 tôlā' is called “crimson” also. Karmîl, on the other hand, is referred to as “crimson” in 2 Chronicles 2:7 and 14.
It would seem that the important verse, Isaiah 1:18, is meant to convey that though your sins are as scarlet (as the dye produced by the kermes), they shall be as white as snow.
International Standard Bible Encyclopedia (1915)
(tola`ath shani (Ex 25:4, etc.)): Cermes vermilio, a scale insect from which a red dye is obtained.