Collectors in warm countries should give their attention to the chigoes and their allies, which are of great interest and have been little studied. They are found on mammals and birds in tropical and semi-tropical countries. The males are very difficult to find, but the females are large and very parasitic. They have the appearance of a small wart firmly fixed to the skin. Small mammals may be transferred, with their chigoes attached, to a bottle of alcohol. Many examples of these insects are often found together on the more naked portions of their hosts. APPENDIX D BIBLIOGRAPHY A. General Bibliography of the chief and most recent works. Many have bibliographies of earlier works. 1. TASCHENBERG (1880), _Die Flöhe_. Halle. Although the author only describes 30 species, his book forms the basis of all subsequent scientific work. He divides fleas into (_a_) chigoes, (_b_) non-chigoes. Plates. Bibliography. References to 73 earlier writers. 2. KARSTEN (1864), _Beitrag zur Kenntniss des Rhyncoprion penetrans._ Bull. Soc. Imp., Moscou. Vol. XXXVII., p. 72. A full account of the life and habits of the chigoe. Many references to older writers and travellers. 3. WAGNER (1889), _Aphanipterologische Studien._ Hor. Soc. Ent. Ross. Vol. XXIII., p. 199; (1893) Vol. XXVII., p. 347; (1898) Vol. XXXI., p. 539; (1902) Vol. XXXV., p. 17; (1903) Vol. XXXVI., p. 125. A series of learned papers by a professor at the Russian University of Kieff. He has also written in Russian. 4. DAMPF (1907), _Die Ost-und Westpreussische Flohfauna._ Schriften der Physik.-ökonom. Gesellschaft zu Königsberg-i-Pr., XLVIII. Jahrgang, p. 388. Contains an excellent general account of our present knowledge of fleas. Short Bibliography. 5. DAMPF (1910), _Palæaeopsylla Klebsiana n. sp. ein fossiler Floh aus dem baltischen Bernstein_. Schriften der Physik.-ökonom. Gesellschaft zu Königsberg-i-Pr., LI. Jahrgang, II. 248. Good plates of the fossil flea in amber. 6. OUDEMANS (1909), _Neue Ansichten über die Morphologie des Flohkopfes sowie über die Ontogenie, Phylogenie und Systematik der Flöhe_. Novitates Zoologicæ, Vol. 16, p. 133. Suggests a new classification based on the morphology of the head, viz. (1) Integricipita; (2) Fracticipita. By the chief authority on fleas in the Netherlands. He has also written numerous papers in Dutch. 7. JORDAN and ROTHSCHILD (1908), _Revision of the non-combed eyed Siphonaptera_. Parasitology, Vol. I., p. 1. Plates. Bibliography. An excellent piece of work, which includes an account of the plague fleas. 8. JORDAN and ROTHSCHILD (1906), _A Revision of the Sarcopsyllidæ_. Thompson Yates and Johnston Laboratories Reports, Vol. VII., p. 15. Plates. Bibliography. The best modern account of the chigoes. 9. BAKER (1904), _A revision of American Siphonaptera or Fleas together with a complete list and bibliography of the group_. Proc. U.S. National Museum, Vol. XXVII., p. 365. Plates. Bibliography of special papers only.