30 Bulletin American Museum of Natural History. [Vol. XXIII^ 



"Morphologically these pscudogynic workers may be characterized as 

 an abortive combination of the thoracic structure of the female with the 

 stature and gastric development of the w^orker; they impress one as frustrate 

 workers, that have borrowed a female thorax. Their size, according to my 

 observations, which extend over materials from a great number of colonies,. 

 is rarely greater than that of the average normal workers of the same colony,, 

 often considerably less. The head and gaster are small, the former, in its- 

 relatively small dimensions, more like that of the female than the worker. 

 The ovaries are, if anything, more feebly developed than in the ordinary 

 workers. The mesonotum is hunched, disproportionately large compared 

 with the pro- and epinotum, and is usually relatively higher than in the 

 female. In many specimens the scutellum is large and separated off by a 

 transverse suture from the mesonotum. The postscutellum [metanotum], 

 on the contrary, is barely indicated, although in some individuals it forms a 

 distinct narrow strip, while the scutellum is not separated oft' in front, but 

 instead divided into two halves by a longitudinal line which is lacking in the 

 female." Wasmann has found the pseudogynes most frequently in the nests 

 of F. sanguinea, more rarely with F. rufa, prate7isis and fusca. When the}' 

 occur they often make up from 5-7% of the personnel of the colony, more 

 rarely as much as 20%. "The coloration of the pseudogynic workers is 

 almost without exception paler than that of the normal workers. This is 

 especially true of the thorax; the color of the head, however, is often darker 

 than in the normal workers of the same colony, and corresponds to the 

 darker head of the female. The slight color variation in the pseudogynic 

 sanguinea is explained by the fact that in this species the female and worker 

 are very similarly colored. Conditions are different in F. rufa and pratensis. 

 Here the color of the pseudogyne, although generally more like the darker 

 tint of the female, is much more variable. In some fully mature indi- 

 viduals it is paler than in the palest workers of the same colony. . . .All 

 pseudogynes are, as Forel observed, cowardly and indolent. Not one of 

 them attempted to bite me while I was plundering their nests, though I 

 often knelt near them for hours while sifting out the myrmecophiles. The 

 very opposite was true of the normal workers, which defended themselves 

 with fury. The pseudogynes act as if they regarded themselves as frustrate 

 existences. In several of the observation nests of F. sanguniea kept in my 

 room, they neither took part in excavating the earth nor in nursing the brood; 

 they did more running about, however, than the females. Their vitality 

 seems to be feebler than that of the normal workers, for none of them man- 

 aged to survive a captivity of several months, although some were callows 

 and the remainder of the colony was in a prosperous condition." 



Transitions between the pseudogynes and the normal workers on the 



