A wool strip (לשון של צמר) colored red using the famed תולעת שני dye is a required ingredient for the Tahara process of he/she who’s skin nega has receded from it’s state of tumah.

What is שני תולעת?

Tosefta and talmud yerushalmi describe the תולעת שני as a worm, this is the approach adopted in a work specific to this study1)1 who pin’s the שני תולעת as the red kermes dye produced from the kermes insect found in the oak trees in northern Israel, a location some consider as hinted to by the tosefta (menachot 9 6) which states that the שני from anywhere but the mountains is invalid;

תכלת אין כשרה אלא מן החלזון שלא מן הילזון פסולה. שני התולעת מן התולע שבהרים הביא שלא מן התולעת שבהרים פסולה

The rambam,2)2 Medrash hagadol (מדה״ג שמות כה א) and rabbeinu bchaya define תולעת שני as being derived from red seeds similar in size to the seeds of the חרוב that are similar on color to sumac berries. rabbeinu bchaya writes the same (שמות כה ג), regarding the parah aduma and reasons that the coloring cannot possibly be derived from an insect which is prohibited by the Torah for oral consumption.

The Torah sometimes calls this color שני תולעת and sometimes תולעת שני, in this instance, the wool strip is to be colored only from the red color derived from the תולעת (as other colors are derived as well)

The wool
A tongue of wool weighing a shekel (apprx. 11.21 gram) is red-dyed using the שני תולעת dye

The water
A reviith of spring water

 

References   [ + ]

1. 1
2. 2