INTERRELATIONS OF INSECTS 33 z 



species may occur. In some species of ants several types of 

 workers exist; these are distinguished by structural peculiari- 

 ties of one kind or another, which possibly indicate special 

 functions, for the most part as yet unascertained. Further- 

 more, 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 ferti- 

 lized, and the differences between worker and queen and be- 

 tween workers themselves may be due to the quality and quan- 

 tity 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. Comstock 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 helpless 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 w-anderings. 

 Ants in general know how to utilize all sorts of existing cavi- 

 ties 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. 



