Prof. 0. Heer on the House Ant of Madeira. 331 



ments, on the other hand, blackish -brown. At times the dark 

 brown extends further, over even the hinder edge of the first 

 segment ; but still more frequently it is more contracted, forming 

 only a dark band over the hinder edge of the second and the 

 (whole of the) third segment. 



III. Conclusion. 



Comparing with each other these four different kinds which 

 compose a colony of (Ecophthorce, we find that the males differ 

 altogether from the rest in the structure of the head. The 

 females, soldiers, and labourers approach each other closely in the 

 structure of the parts of the mouth, in the legs, and in the equal 

 number of the abdominal segments; yet the labourer differs 

 much from the female, not only in being so much smaller, but 

 by its smooth head, its serrato- dentate mandibles, different struc- 

 ture of the thorax, owing to the want of wings, as well as by the 

 form of the second joint of the abdominal pedicle. In size, structure 

 of the mandibles, and striated head, the soldier forms a middle 

 link between the female and the labourer ; but, on the other hand 

 again, it differs much from both in its excessively large perfectly 

 heart-shaped head, and in the shape of the mesothorax ; assuming 

 thus quite a peculiar aspect. These forms are very distinctly 

 marked ; and amongst the numberless specimens seen by me of 

 this ant, no intermediate link between the labourer and soldier 

 ever has occurred. In Atta capitataj Latr., which I have ob- 

 served in great numbers on the Guadalquivir at Seville, as well 

 as in several other places in Spain, labourers with small heads, 

 and soldiers with large, occur also ; but, between these, trans- 

 itional forms are found, which is never the case with our (Eco- 

 phthora. That the soldiers cannot possibly be slaves captured 

 from other nests (a circumstance of known occurrence amongst 

 the Amazon-ants), is proved as well by their very constant 

 occurrence in the pupa and perfect state in the nests of the 

 (Ecophthorcs, whilst they are never found alone, as by their agree- 

 ment in all essential organs (in their trophi, antennae, and legs) 

 with the labourers and females. Such a marked distinction 

 between the two neuter forms as in (Ecophthora has not else- 

 where been observed. Something similar, however, seems to be 

 the case in several species of the Southern Hemisphere, only it 

 has not usually been rightly understood. We have seen above, 

 that in the Train and Driver Ants two forms of neuters are 

 found, and also in Atta capitata, Latr., which must not be con- 

 sidered as varieties, but as forms, each of which has its own 

 special and peculiar position in the ant-oeconomy. Nay, even 

 amongst several of our own species, attentive observation points 



