Tortricidae, 188. Trachea, iv. Tracheae, absence of in Polynema, 165. Tracheae, origin of, 171. Tree cricket, 216. Trichocera hyemalis, 189. Trichodes, 42. Trigona, 18. Trochilium tipuliforme, 205. Trombidium, 120, 159. Trouvelot, L., on amount eaten by silk worms, vii, 60. Turnip butterfly, 197. Uhler, P. R., on habits of the dragon fly, 107, 110. Verrill, A. E., on the parasites of man and the domestic animals, 84. Vine dresser, 59. Virgin reproduction, 168. Wasp, 206. Water bear, 150. Water boatman, 166, 209. Waterhouse, G. R., on habits of Osmia, 27. Weevil, 179, 188, 194. Weismann on growth of insects, 164. West, Tuffen, on the foot of the fly, viii. Wheat midge, 197. Wine fly, 83. Wingless insects, 171. Wings of insects as respiratory organs, 165. Wings, origin of, 172. Worthen's discovery of fossil insects in Illinois, 158. Worms, the ancestors of insects, 160, 169. Wyman, Jeffries, on the cells of the honey bee, 17. Xenos, 46. Xylobius, 159. Xylocopa, 21. Zaddach on development of worms, insects and crustaceans, 169. Zoea, 156. _The only American Text Book of Entomology._ A Guide to the Study of Insects, Being a popular introduction to the study of Entomology, and a treatise on Injurious and Beneficial Insects, with descriptions and accounts of the habits of Insects, their transformations, development and classification. By A. S. PACKARD, Jr., M. D., Curator of Articulata at the _Peabody Academy of Science_, Lecturer on Entomology at _Bowdoin College_, and Entomologist to the _Mass. State Board of Agriculture_. Containing 715 pages, 15 full page plates and 670 cuts in the text, embracing 1260 figures of AMERICAN INSECTS. In a large octavo volume, printed on extra paper and in full cloth binding. Third and Improved Edition. Price reduced to $5.00. The GUIDE has already been introduced either as a text-book, or for reference, in _Harvard University_, _Williams College_, _Dartmouth College_, _Antioch College_, _Massachusetts Agricultural College_ and other institutions in this country, and in _Oxford_ and _Cambridge Universities, England_. _Published by the NATURALISTS' AGENCY, Salem, Mass._ * * * * * _We give a few of the large number of testimonials relating to the character of this work._ Not only does your book fully justify its title for its clearness and the concise presentation of a difficult subject, but it is emphatically a guide to the study of insects injurious to vegetation, owing to the constant reference it contains to topics pertaining to economic entomology. I will say more: I hold that your work ought, in connection with Harris's "Treatise on Insects Injurious to Vegetation," to which it is, as it were, the Key, to be introduced in all our Agricultural Colleges, as the best text-book of that kind now extant.--_Extract from letter of Prof. L. Agassiz._