Library

The horsefly (Machong, 虻虫) resembles the woodlouse (Shufu, 鼠妇). The larger specimens are slightly over one cun in length, flat in shape like a turtle, with a hard shell resembling scales, featuring eight transverse stripes on the back. Its eyes and six legs are concealed beneath the shell. It has a slight foul odor, similar to that of a cockroach (Feileng, 蜚蠊). This species is not native to our country; it is an imported medicinal material from China. I have kept large quantities of them and used them clinically, repeatedly achieving effective results.

Its primary indications are blood stasis (Yuxue, 瘀血) presenting as hardness and fullness in the lower abdomen (Shaofu, 少腹). It is also used for mania (Fakuang, 发狂), heat due to blood stasis (Yure, 瘀热), forgetfulness (Xiwang, 喜忘), and irregular menstruation (Jingshui Buli, 经水不利) in women.

In the syndrome description for Didang Tang (Cistanche and Rhubarb Decoction), it states: "Hardness and fullness in the lower abdomen." It further states: "There is long-standing blood stasis." And again: "There is blood stasis."
The formula uses thirty Machong (虻虫).

In the syndrome description for Didang Wan (Cistanche and Rhubarb Pill), it states: "Fullness in the lower abdomen, which should be accompanied by difficulty in urination. Now that urination is normal, this indicates the presence of blood stasis."
The formula uses twenty Machong (虻虫).

Based on these two formulas, it is clear that Machong treats blood stasis. It is used in conjunction with Leech (Shizhi, 水蛭), so they are often prescribed in equal proportions. However, the decoction uses thirty units, while the pill uses twenty units. The condition treated by the decoction is acute, whereas the condition treated by the pill is chronic or mild. Therefore, the dosage differences reflect the urgency of the pathology.

Huainanzi states: "Machong breaks up accumulated blood." Liu Wansu stated: "Machong feeds on blood and thus treats blood disorders, utilizing its natural nature for therapeutic effect." Examining the indications for using Machong in various formulas: "breaking up accumulated blood," "expelling blood," "accumulated blood," "long-standing blood stasis," "presence of blood stasis," "menstrual obstruction in women," "presence of blood," "blood should be purged," "heat due to blood stasis in the interior," "mania-like state," and "forgetfulness"—all of these are definitive signs of blood disorders. However, this does not imply blood stasis throughout the entire body. It specifically targets blood stasis located in the lower abdomen, where this herb can purge it. Thus, "hardness and fullness" or simply "fullness" of the lower abdomen serves as the clinical indication for its use, regardless of whether other signs of stasis are explicitly confirmed.

During summer, Machong frequently flies and bites humans, cattle, and horses to suck their blood. Small ones resemble bees, while large ones resemble small cicadas. They look like flies, with prominent eyes and a concave, oblique abdomen, appearing yellowish-green. Some claim they transform from leeches. They are occasionally seen swarming in mountains and open fields. Thus, the larger ones may transform from mountain leeches, and the smaller ones from water leeches; both are used medicinally. Duan Chengshi stated: "In southern streams and creeks, there are many water maggots, over one cun long, black in color, which transform into horseflies at the end of summer." Note: "Water maggots" is likely a textual error for "water leeches," as the characters for maggot (Qu, 蛆) and leech (Zhi, 蛭) are visually similar.