Acta Ac. German. xxxiii. 1869, No. 2, p. 81.
Seventeenth Rep. Insects Illinois, 1891, p. 66.
Kessler, Acta Ac. German. li. 1887, pp. 152, 153.
In connection with this the absence of a functional mouth in the imago state of numerous Lepidoptera, and of Oestrid Diptera, should not be forgotten.
Horae Soc. ent. Ross. xxiv. 1890. p. 386.