272 ENTOMOLOGY 



respect to the number of forms under which a single species may occur. 

 In some species of ants several types of workers exist; these are distin- 

 guished by structural peculiarities of one kind or another, which possibly 

 indicate special functions, for the most part as yet unascertained. Fur- 

 thermore, the sexual individuals are not necessarily winged; some or all 

 of them may be wingless, especially the females. These wingless males 

 and females are termed ergatoid, on account of their resemblance to 

 workers. 



As to how these various forms are produced, very little is known. 

 Probably, as among bees, workers and queens are produced from the same 

 kind of eggs, which have been fertilized, and the differences between 

 w r orker and queen and between workers themselves may be due to the 

 quality and quantity of the food that is supplied to the larvae by their 

 nurses. As in bees, the parthenogenetic eggs laid by abnormal workers 

 may produce males, as Forel, Lubbock and Miss Fielde have found; or 

 they may produce normal workers, as Reichenbach and Mrs. A. B. Corn- 

 stock have found to be the case in Lasius niger. Wheeler points out 

 the possibility of the inheritance of worker characters through the male 

 offspring of workers. 



Larvae. The numerous eggs laid by one or more queens are taken 

 in charge by the young workers, through whose assiduous care the help- 

 less larvae are carried to maturity. The nurses feed the larvae from their 

 own mouths, clean the larvae, and carry them from one place to another 

 in order to secure the optimum conditions of temperature, moisture, etc. 

 When a nest is broken open, the workers seize the larvae and pupae and 

 hurry into some dark place. The pupa is either naked or else enclosed 

 in a cocoon, spun by the larva. 



Nests. The species of the tropical genus Eciton do not make nests 

 but occupy temporarily any suitable retreat which they may happen to 

 find in the course of their wanderings. Ants in general know how to 

 utilize all sorts of existing cavities as nests; they make use of crevices 

 in rocks and under stones or bark, the holes made by bark-beetles, hollow 

 stems or roots, plant-galls, fruits, etc. The extraordinary "ant-plants" 

 have already received special consideration. 



Very many ants excavate their nests in the ground; after a rain these 

 ants are especially industrious in the improvement of the nest, pressing 

 the wet earth into the walls of the galleries and adding probably a se- 

 creted fluid which acts as a cement; stones and sticks are often worked 

 into the walls of a nest and the mounds of ants are frequently fashioned 

 about blades of grass or growing herbage of whatever kind. The sub- 



