Note 4 — Chapter I
Reading edition
The Pyrophorus noctilucus, or "cucujo," found also in Mexico and the West Indies. It resembles our large spring-beetle. The light proceeds from two eye-like spots on the thorax and from the segments underneath. It feeds on the sugar-cane. On the Upper Amazon we found the P. clarus, P. pellucens, and P. tuberculatus. At Bahia, on the opposite coast, Darwin found P. luminosus, the most common luminous insect.