iv DORYLIDES DRIVER ANTS 179 



respects similar to Eciton in habits, as they enter human habita- 

 tions and cause nearly everything else to quit ; it is probable 

 that they are also exclusively carnivorous. Savage detected the 

 nests of A. arcens, but the account he has given of them is too 

 vague to permit one to decide whether the assemblages he saw 

 were of a nomad kind. The workers of this species vary greatly 

 in size, and Emery has 

 recently stated that 

 he believes all the 

 supposed species of 

 the genus to be 

 merely varieties of A. 

 burmeisteri. The 



female of the driver FIG. 80. Body of male of Dorylus sp. Delagoa Bay. 

 mf! i ssHll nnifp a ' P ron tum ; b, c, divisions of mesonotum ; d, 



metanotum ; e, propodeum ; /, first abdominal seg- 

 UllkllOWn. A Dorylus ment ; g, h, points of insertion of anterior and pos- 



has been ascertained terior wings. 



to be the male of Typhlopone. The male Dorylus (Figs. 79, A, 

 and 80) is of great interest, for the propodeum is in a more primi- 

 tive form than it is in any other petiolate Hymenopteron known to 

 us, while at the same time the pronotum and mesonotum are very 

 highly developed. The genus Typhlatta Sm. has been recently 

 identified by Wroughton and Forel as the worker-condition of 

 which Aenictus is the winged male. The genus Alaopone will 

 probably be found to have some species of Dorylus as its 

 male. 



The females of the Dorylides are amongst the rarest of Insects, 

 and are also amongst the greatest of natural curiosities. Although 

 worker auts and female ants are merely forms of one sex the 

 female yet in this sub-family of ants they have become so 

 totally different from one another in size, form, structure, and 

 habits that it is difficult to persuade oneself they can possibly 

 issue from similar eggs. In the Insect world there are but few 

 cases in which males differ from females so greatly as the 

 workers of Dorylides do from the females, the phenomena finding 

 their only parallel in the soldiers and females of Termites ; the 

 mode in which this difference is introduced into the life of the 

 individuals of one sex is unknown. The largest of all the 

 Dorylides are the African Insects of the genus Rliogmus. Only 

 the male is known. 



