--The neotropical genus Harpagus is usually placed with the kites. It is characterized by two "teeth," on the upper mandible. The scientific names of the two species of the genus, diodon and bidentatus, both reflect this fact. The latter, which is the more widespread of the two, is called the Double-toothed Kite. Such "teeth," which are doubt. less adaptations for dismembering food, are not unusual in kites. Thus the species f the Old World genus Aviceda have variously one or two such dentides, whereas the American Gray-headed Kite of the genus Leptodon, a close ally of .4viceda, has one. Some early authors, such as Sharpe in the "Catalogue of Birds in the British Museum," placed these toothed kites in the Falconidae, but it was soon realized that they have nothing to do with that family. Hapagus is less obviously a kite than are Aiceda or Leptodon. In proportions and color it is somewhat like many accipiters. Loye Miller (Condor, 39, 1937:219-221) in a paper on the affinities of Harpgus remarked: "the general appearance of the bird when I picked it up was that of an Acclpiter with an abbreviated tail .... "Professor Miller prepared a skeleton of this bird which he compared with those of a White-tailed Kite (Elanus), a Cooper Hawk (Acdp/ter cooperS), and a Merlin (Falco columbarius). He found Harpagus very different from Falco in most of the characters compared. On the other hand, in several respects he found the osteolugy of Harpagus more like .4cciplter than like Elanus. These data have recently been used to bring the systematic position of the genus again into question. Hellmayr and Conover (Cat. Birds Amer., pt. 1, no. 4, 1949:32, footnote), although leaving Harpgus in the "Milvinae," state: "According to Miller skeletal characters of this form reveal its close kinship to Accipiter." I am not competent to discuss Miller's osteological comparisons in detail but would merely sug- gest that the similarities to Acclpiter and the differences from Elanus may be superficial adaptations. In one comparison this is clearly stated to be the case: Elanus has a type of humerus usual in sailing birds; the other two do not. I feel that if the comparison had been with a kite of more or less similar proportions the results might have been very different. Gurney (Ibis, 1881:118-124) in a paper on Harpagus states: "Mr. Ridgway informs me 'it is most nearly related, osteologically, to Ictila.'" The latter, of course, like Elanus, is a long-winged gliding kite, but at least it belongs to the same "subfamily" of kites as does Harpagus, assuming, as I believe to be the case, that the latter is a kite. In any event, Miller was not at all emphatic about his conclusions. He merely listed certain similarities between Harpagus and Acclpiter without implying that its status was finally settled. Gurney also noted that Nitzsch had found the pterylugraphy of Harpagus to be similar to that of Baza (= A/ceda). In a paper just published, Vesta and Erwin Stresemann (Jour. f. Ornith., 101, 1960:394) state that they found the wing molt of Harpagus to be typical of the kites of the railvine group. They also note that Suschkin had reached the same conclusion about the position of the genus in his work on the diurnal raptores. The "reputation" of Harpagus has been influenced by some field notes of the junior author of "The Birds of the Santa Marta Region of Colombia" by W. E. Clyde Todd and M.A. Carriker, Jr. (Ann. Carnegie Mus., 14, 1922:146), where it is portrayed as a very savage little hawk that "feeds entirely upon small birds." We are not told the source of the evidence for this rather sweeping state- ment beyond the fact that a captive specimen ate small, dead birds. Knowledge of this hawk was enhanced by Laughlin's account (Condor, 39, 1937:137-139) of a pair that nested on Barro Colorado Island, Panama. He refuted the bird-eating habits and found that Harpagus feeds upon large insects and lizards, securing the latter by a chase "up a slanting branch, hopping after it--not flying--with wings spread to maintain balance. This method of hunting, although it looked clumsy, was apparently successful .... "I have found four other references to the food of Harpagus in the literature or on specimen labels. All refer to insects; one refers also to reptiles. Mr. Eugene Eisenmann, who has had considerable experience with Harpagus, including observa- tions of the pair studied by Laughlin, tells me that small birds usually are unconcerned when a mem- ber of this genus is nearby. Wetmore (Proc. U.S. Nat. Mus., 87, 1939:184) was made aware of the presence' of Harpagus by the alarmed chirping of a large hummingbird, Cyanolesbia, and Eisenmann saw one chased off by a pair of Streaked Flycatchers (Myiodynastes macu/atus). Hummingbirds and tyrant flycatchers are, however, unusually pugnacious birds. The problem of possible mimicry among birds of prey is one which still awaits clarification. Tbe following paragraph from Newton's article on this subject in the "Dictionary of Birds" (p. 574) is of interest: "On the information of Mr. Salvin, Mr. Wallace has cited (Contrib. Nat. Sdect. p. 107) another very curious case of Mimicry in Birds. This is furnished by Acdpter peatus, a widely-ranging species of Sparrow-Hawk which near Rio Janeiro departs from the plumage it wears in other places to assume that of Harpagus diodon, a local species of insectivorous habit, with the object, as suggested, of deluding small birds into the belief that it is harmless in character. The similarity here extends to both immature and adult plumages, which are very different." It should be pointed out that although the adult and immature plumages of Acdpiter bicolor pieatus are very like those of Hartgus diodon, it is not, of course, definite that the former has departed from its usual coloration only in the range of diodon or that the resemblance has any special significance. Races of bi,olor with streaked immatures are found beyond the range of diodon; conversely, the northern half of the range of diodon has another race of Accpiter in which the iramatures are immaculate white ventrally and quite unlike those of diodon. A further point is that, assuming there is mimicry involved, we do not know whether the more predatory species (Acclpter) is mimicking the inoffensive one (Harpagus) or vice versa. As Meyer and Wiglesworth (Birds of Celebes, 1, 1898:66-72, color pls. 2 and 3) state in their lengthy discus- sion of the remarkable similarity in all plumages between a honey-buzzard kite (Pernis celebensis) and the eagle (Spzaetus lanceolatus) it is possible that the inoffensive kite might obtain relief from enemies, presumably nest predators, by resembling the eagle. They conclude, however, that both species are so uncommon that it is difficult to postulate mimicry upon any basis whatever. If Harpagus does mimic accipiters, this was of little avail in the pair observed by Laughlin. One of the pair was rather easily frightened from the nest by a toucan (Rampkastos) which proceeded to eat the kite's egg! In summary, one may conclude that Hartgus is not related to Accipter and that the resemblance between the two may possibly, although this is unlikely, represent mimicry.--DEAN AAOO, Ameri- can Museum of Natural History, October 31, 1960.