Cœlioxys, difficulty of their specific separation, 267. general observations on, 267. geography of, 74. list of native species, 267. parasitical on Megachile and Saropoda, 267. scientific description of, 265. Collar, 41. Colletes, general observations on, 187. geography of, 64. list of native species, 187. natural history of, 187. parasites upon, 190. scientific description of, 185. Colour of bees, 60. more intense in males than females, 52. most conspicuous in parasites, 66, 105. Combs, structure of, 345. Corbiculum, 319. Correlative relations of structure and function, 10. Cotton, Rev. Chas. Wm., a distinguished apiarian, 361. Coxa, or hip, 41. useful as a specific character, 42. Compound eyes, 26, 27. Compressed, when the transverse section is shorter than the vertical. Constricted, with tightened edges. Conterminous, where the joints follow each other in a straight line of succession. Crenulated, cut into segments of very small circles. Cubital cells of wings, 45. cuckoo-bees = Nudipedes, 249. ‘Cui bono?’ answer to, 141. Curtis, inferior merit of his system, 152. Dasygasters, artisan bees, 167, 269. Dasypoda, general observations on, 225. geography of, 69. native species, 225. natural history of, 226. scientific description of, 224. Deflected, when bent downwards. Dentate, toothed. Depressed, when the vertical section is shorter than the transverse. Describers, duties of, 125. Describing, modes of, before Linnæus, 129. Differences of appearance between the parasite and the sitos, 260. Digiti, anterior tarsi, 42. Dissimilarity frequent between the sexes, 52. Domestication of animals, 5. Dorylus, 311. Drone = male bee, description of, 323. Edentate, without teeth. Egg of bees, 18. Egyptian hieroglyphics and sculptures represent the bee, 6. Elenchus, habits of, described by Dale, 113. infests Halictus, 113, 219. Elliptical, oval but with the longitudinal diameter more than twice the length of the transverse. Enemies of bees, 51. Epeolus, general observations on, 260. geography of, 73. native species, 260. parasitical on Colletes, 190, 260. scientific description of, 258. Epipharynx, 29, 30. Eucera, general observations on, 232. geography of, 70. infested by Nomada sexcincta, 235. native species, 232. natural history of, 234. scientific description of, 231. Face of bees, 26, 27. Families, characteristics of, differ, 136. Family, 134. Feeling of bees, 56. Femur, or thigh, 41. Fertilization of flowers produced by bees, 11, 51. Feuds of animals, the occasion of, 352. Filiform, thread-like, of uniform thickness. antennæ, 28. Fimbriated, = fringed. Flagellum of antennæ, 18. Flight of bees, variation of their modes, 49. Floral clock of Linnæus, 50.