
708 THE AMERICAN NATURALIST. | [Vor. XXXVI. 
I trust that these tables will facilitate the labor of identifica- 
tion and enable those who are beginning to study the exotic 
ants to find their way more easily. I am well aware of the 
fact that one may find one’s self in doubt at certain bifurcations 
of the path. How is one to know, e.g., whether the worker is 
dimorphic, when one has only a single specimen of the species? 
I have made no use of such characters except when I had noth- 
ing better to present, and then I have tried to reinforce them 
as much as possible with accessory characters. Sometimes I 
have cited characters peculiar to the males and females, as these 
are often the most important in distinguishing certain genera, 
the workers of which present only feeble or insignificant differ- 
ences. Nevertheless, I decline to attempt for the present an 
analysis of the sexual forms, which are still too imperfectly 
known. 
In the enumeration of the segments of the abdomen I 
include the one or two constituting the pedicel, so that the 
segment following this, and usually designated by other authors 
as the first abdominal, is for me the third in the Myrmicine, 
the second in the Camponotinz, etc.; the last visible segment 
is, therefore, always the sixth in the females and workers, the 
seventh in the males. In the male I designate as “ subgenital 
lamina " what is usually, but improperly, called the hypopygium 
and is in reality the ventral lamina of the eighth segment. 
For the anatomy of the gizzard and the poison apparatus I 
would refer the reader to the works of Forel, Dewitz, and 
myself.! 
Having adopted the dichotomic form for the identification of 
the genera, it follows that the order cannot express their 
natural affinities; but this can lead to no inconvenience in à 
1 Forel, A. Etudes paps age en 1878. Anatomie du Gésier des 
Fourmis, Zu Soc. Vaudoise Sc. Nat., vol. xv (1878), pp- 339-362) Fl. XXIII ; 
Der Giftapparat und die Analdruesen yes Ameisen, Zeitschr. f. wiss. Zool., Bd. xxx, 
Suppl. (1878), pp. 28-68, Taf. ITI-IV. 
| witz, H. Ueber Bau und Entwickelung des Stachels der Ameisen, Zeitschr. 
Jf. wiss. Zool., Bd. xxviii (1877), pp- 527-556, Taf. I. 
Emery, C. Ueber den sogenannten ers einiger Ameisen, Zeitschr. f 
wiss. Zool., Bd. xlvi (1888), pp. 378-412, Taf. XXVII-X 
In the Loss will be found figures of all the forms of w gizzard in the 
