The student will find important information as to the varieties of external form of pupae in Dr. T. A. Chapman's writings; see especially Tr. ent. Soc. London, 1893, 1894, and 1896.
Latter, Tr. ent. Soc. London, 1895, p. 399.
Bull. Soc. Vaudoise, xxx. 1894, No. 115.
Zeitschr. wiss. Zool. liii. 1892, p. 623.
Zool. Jahrb. Anat. iii. 1889, p. 646.