Transcriber's Note:
The twenty-five engraved illustrations of adult woodlice shown in Plates I to XXV at the end of the book have been prepared with thumbnails which preserve the same scale as the original book. Clicking on one of these thumbnail images, or on most other figures in the text, will display a larger image to the same scale.
Obvious typographical errors have been corrected. Inconsistent accents, punctuation, and hyphenation are as in the original text.
The "æ" ligature is used interchangeably with "ae" throughout.
Some taxonomic names may have changed since 1906.