Note 558 — LETTER XL.
Reading edition
Ibid. t. xix. f. 2. K L. This organ seems analogous to that with four retractile fleshy horns, observed by Reaumur and De Geer in other species of Muscidæ. Reaum. iv. t. xxviii. f. 13. a, s. De Geer vi. t. iii. f. 18. c, d.