AMERICAN HYMENOPTERA. 287 



The workers or neuters may be regarded as undeveloped females, 

 and accordingly we find them assimilated to the female in the struc- 

 ture of the mandibles, the number of abdominal rings and the number 

 of joints upon the antennse. The major also resembles the queen in 

 the size of the head. The legs of all the workers, at least in length, 

 more nearly approach the male. The common diiferences between the 

 workers and the two sexes are very marked : first, the absence of 

 wings; second, the shape of the thorax, which in the female and male 

 is roundish and wide, and in all the workers is narrower at the pro- 

 thorax, compressed and wedge-shaped below. (See PL IV, figs. 1 — 5.) 

 Third, the absence of the three oscelli upon the base of the caput, a 

 difference which is very curious. I conjecture that it has some re- 

 lation to the fact that the females and males alone are designed to 

 traverse the air, as in the " marriage flight," and that the oscelli are 

 servicible to direct their course at that time. On this theory one can 

 understand why the workers are simply supplied with the characteristic 

 compound eye. However, if as Huber supposes, the worker ant can 

 be developed at will (as with bees), into a fertile queen from the grub, 

 by special feeding and care, it is difficult to see how the oscelli are also 

 developed. I could trace no " germ " of them by ordinary working glass. 

 The females were very numerous, and it would be difficult to conceive 

 the lack of a queen in a colony so well supplied as this one. 



The three forms of workers, have very apparent differences among 

 themselves. The major although about the same length as the minor, 

 is stouter, and especially is distinguished by superior size of the head. 

 In this respect and in general form the major closely resembles the 

 female, while the minor and the dwarf more nearly approach the male. 

 The small minor or dwarf has the small head and is but half the size 

 of the minor-large, of which it is simply a reduced form. The shape 

 of the scale throughout all the worker and female forms is the same. 

 In the male it is shorter, more notched at the tip, thicker at the base 

 and stands more erect upon the pedicle. [PI. IV, fig. 7.] 



•These differences in structure among the working members of the 

 formicary start inquiries as to the functions and offices of each. Have 

 all the same duties? If so, why such marked difference? If the 

 variation in structure does indicate a variety of office, what are the 

 several duties of the worker classes? It may contribute something 

 to the solution to say that, at the original opening of the beam, the 

 worker major was the only form that seemed disposed to attack me. 

 On offering my finger to one of these it was immediately seized, and 

 pinched again and again with much rigor. It seemed thus to be the 

 veritiible soldier of the republic. The queens and males made no 



