﻿378 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loo 



when the bird was freshly killed, in company with the true host 

 {Dendrocygna) . Since viduata is one of the two species of Dendro- 

 cygna found in the same geographical range with Alopochen aegyptia- 

 cus (and is the more widely distributed of the two) it seems logical 

 that it is the true host. Even if Kudow's type had been taken from 

 a zoo specimen the chances are that it came from D. viduata^ since that 

 is the species most likely to have been present in the zoological garden 

 with Alopochen. 



Having recently collected specimens of Acidoprocttis from Dendro- 

 cygna autmnnalis discolor, I requested from Dr. Hopkins the loan of 

 specimens of A. rostratus for comparison with them. He very kindly 

 sent me a series of 5 males and 11 females collected in the Transvaal, 

 asking me to designate a pair of neotypes to be deposited in the British 

 Museum, to keep neoparatypes for myself, and to return the remainder 

 to him. 



A comparison of A. rostratus with my specimens from D. a. dis- 

 color from Colombia strengthens the contention of Dr. Hopkins re- 

 garding the true host of the former, since its affinities are clearly 

 with my specimens from D. a. discolor rather than with A. ta^chen- 

 hergi Hopkins from Alopochen, with which it has been directly com- 

 pared. In addition, A. rostratus, as Dr. Hopkins says is a "brown" 

 form, while taschenbergi, moschatae, and kelloggi are pale-colored, 

 with sharply defined dark markings,. 



The species described below from D. a. discolor is also a brownish 

 form with dark markings not sharply defined or prominent. The 

 same type of genitalia is found in the four species mentioned above, 

 except that the endomera are strikingly different in all of them. The 

 chaetotaxy of the genital plate in the females is also similar in the 

 four species and seems to be characteristic of the genus. All four 

 forms differ in the shape and proportions of the preantennary area 

 of the head, the frontal emargination, and to some extent in the pro- 

 portions of the whole head. The general appearance of A. rostratus is 

 very similar to that of A. hophinsi, especially in the abdominal struc- 

 ture, but the whole insect is much larger. Piaget's figure of the 

 female of A. hifasciatus (= rostratus) is very good (Les Pediculines, 

 1880, atlas, pi. 17, fig. 5), and I have given a figure of the male of 

 hophinsi illustrating the dimorphic abdominal structure of the two 

 species. 



A very unusual character in both rostratus and hophinsi is the sexual 

 dimorphism in the size of the thoracic segments, those of the female 

 being considerably smaller, while the abdomen is larger. In taschen- 

 hergi and kelloggi these segments are slightly larger in the female;. 

 Figures are also given of the preantennary area and male genitalia 

 of both kelloggi Carriker and taschenhergi Hopkins (fig. 45, a-d). 



