BUCKINGHAM. — DIVISION OF LABOR AMONG ANTS. 439 



tudinal mounds ; these are wanting in the small workers. The head 

 of the soldier is much redder, except for the black eyes and the dark 

 regions around the mouth. It is also covered with stronger ridges of 

 chitin and is more pubescent. 



2. The antennae are, relatively to the whole head, much longer in 

 the small ants. The number of joints is the same for both classes, but 

 in the small ants the three distal joints are larger than in the soldiers. 

 The scapes are in form very similar in the two castes, but are relatively 

 shorter in the soldier. The funiculus, although actually slightly shorter, 

 is, in proportion to the size of the head, much longer in the small 

 workers. 



3. The frontal carinae differ slightly in the two forms, being nearly 

 parallel in the small workers, but diverging posteriorly somewhat in 

 the soldiers. 



4. The cl}^eus in the small ants resembles a triangle, somewhat 

 curved outward in front, but in the soldier it has four sides, of which 

 the two lateral diverge anteriorly, and its anterior margin is slightly 

 notched in the middle. 



5. The compound eyes are further forward in the soldier than in the 

 worker. 



6. The mandibles in the small ants are slender, and bear teeth, of 

 which the outside one is especially large, but in the soldier they are 

 very strongly built, blunt, straight-edged, without teeth, and some- 

 what sharp on the edges which come in contact with each other, very 

 much resembling hatchets. 



When the queen (Plate, Figure 21) of this species was examined, 

 it was found that, while she resembles the worker more closely in cer- 

 tain characteristics, she is, on the whole, more like the soldier. 



1. Her whole body is larger than that of the soldier, suggesting that, 

 as in Camjwnotus americanus and C. pictus, she represents one end of 

 a series from which some members have, probably, dropped out. But 

 there is more difference between majors and queens in this species than 

 in Camponotus, and even within each of the two classes, soldiers and 

 minors, — supposedly connected by missing forms, — the gradation is 

 not as uniform as it is throughout the Camponotus series. 



2. Her head is both relatively and actually smaller than that of the 

 soldier. On the other hand, the shape, both in regard to its general 

 proportions and to the posterior margin, more nearly resembles that 

 of the worker ; but the chitinous ridges and the general color closely 

 resemble those of the soldier, though they are less marked. 



3. Certain organs of the head also resemble those of the soldier 

 more closely, viz., the antennae and their parts, the angle which the 



