16 Mr. J. O. Westwood's Description 



II. Description of the "Driver'^ Ants, described in the 

 preceding Article. By J. O. Westwood, F.L.S., &:c. 



The remarkable account of the habits of the Driver ants of tro- 

 pical Western Africa, contained in the preceding article, by Dr. 

 Savage, is too interesting not to require that the species in ques- 

 tion should be entomologically described, so as to be at once 

 identified, and introduced into its place in the family of the ants 

 to which it belongs. Having been requested to drawr up a de- 

 scription of the insects sent in great numbers by Dr. Savage, I 

 herewith offer, by way of supplement to his article, the following 

 characters, with the accompanying remarks. A comparative ex- 

 amination of the different individuals was in fact especially neces- 

 sary, in order to learn the real nature of the different classes, with 

 reference to the question whether the Soldiers among the For- 

 micidce were analogous to the Soldiers among the Termitidce, that 

 is, whether they formed, as in the latter, a distinct class, or whe- 

 ther they were merely neuters, with larger heads than usual. 



On carefully examining the specimens which were sent to 

 England in spirits, I found that they varied in length from If 

 to 5 lines, all possessing the same structure not only of thorax, 

 abdomen, legs and antennae, but also of the maxillae and labial 

 apparatus. All likewise agreed in the general structure of the 

 head, the only material difference being that the teeth of the 

 mandibles are more developed in the small individuals than in 

 the large ones ; that the heads in the latter are comparatively 

 larger ; and that in the former there is a more evident carina 

 down the middle of the front of the head. I must confess that I 

 could discover no distinct character to separate the largest indi- 

 viduals from the others; there seemed indeed to be a regular 

 gradation in the size from the largest to the smallest, which the 

 natives appear to consider as females. I thus regard them 

 all as neuter ants, and consider it very unfortunate that we are at 

 present unacquainted with the males and females, or with the 

 larva and pupa state of this interesting insect. These lacunae will, 

 1 trust, be still filled up by Dr. Savage. 



But the most curious circumstance which my examination of 

 these insects made evident was, that all the remarkable economy 

 detailed in the preceding memoir is performed by creatures desti- 

 tute of organs of sight, having been unable to detect the slightest 

 indication of eyes in any of the individuals. 



