212 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 95 
Kéler says: “The type of alzenus is very similiar to your male from 
T. major percautus, but it differs distinctly in the shape of the pro- 
thorax, which in alienus type is distinctly trapezoidal, the points lying 
behind the middle of the sides, as well as in the form of the last seg- 
ment, which in the type alenus is a little longer than wide (336 X 288 
microns) .” 
The material before me (males from six species of Z7namus) shows 
absolutely no variation in the shape of the prothorax. It is true that 
there is some variation in size, but the general shape is the same, agree- 
ing precisely with the shape of the prothorax of O. solitarius of 
Guimaraes and Lane, as shown in the figure published by them. As 
for the last abdominal segment, all males examined (except that of 
O. a. robustus) have this segment exactly as long as broad (ranging 
from 0.27 to 0.303 mm.). In O.a. robustus this segment zs very slightly 
longer than wide (0.297 by 0.285 mm.), but the difference is so slight 
that it has no value whatever. 
Taking the above facts in consideration, I am not prepared to accept 
Dr. Hopkins’s theory (1940, p. 419) that the true host of O. altenus 
(Giebel) is Zinamus solitarius or that Ornicholax solitarius Guimaraes 
and Lane is a Synonym of O. alienus (Giebel). I prefer, until addi- 
tional proof is forthcoming, to recognize O. solitarius and to leave 
O. alienus (Giebel) in the category of “host unknown.” 
Furthermore, Taschenberg (1882, p. 59) distinctly says that he 
examined the type of alienus and found it in several pieces, and for 
that reason he could not give an exact description of it. If the type . 
was in such poor condition as that in 1882, what must be its condition 
today, and how would it be possible to say that it was any one of the 
several closely related known forms, without being able to distinguish 
very clearly the intricate genital armature, whose complicated struc- 
ture is very difficult to differentiate under the most favorable con- 
ditions? 
I have examined a series of Ornicholaw alienus from the following 
husts: Zinamus major castaneiceps (host of O. a. robustus), Pacific 
slope of Costa Rica; 7’. m. fuscipennis, Caribbean slope of Costa Rica; 
T.m. percautus, Mexico; 7. s. serratus, Bolivia; 7’. serratus rujiceps, 
Colombia; Tinamus t. tao, Venezuela and Colombia; 7. tao weddelii, 
Bolivia. 
Unquestionably O. a. taot (from Tmamus tao) is one of the most 
well marked subspecies of alienus. In addition to the male type from 
Venezuela I have a second male from the same host taken in Colombia, 
and two females from 7’. tao weddelli. The male from Colombia is 
extremely close to the type in all particulars, while the two females 
from 7. ¢. weddelli seem also to belong here. The head is not so 
narrow (proportionately) as in the male, but I find that this is true of 
