felFE HISTORY. 41 



24. The micrergate is a worker of unusually small size. It is 

 often present in nests which contain macrergates, as well as in 

 moderate colonies. The first brood of a young queen usually 

 consists of this form. 



25. The gynaecoid is an egg-laying worker. In some families the 

 queen has disappeared and has been replaced by this form of 

 worker. Should a colony lose its queen, one or more workers may 

 become substitute queens, lay eggs, and be treated accordingly by 



Fig. 50. Pterergate of Myrmica scabrinodis. Yelverton, VIII. 1913. 

 (Bondroit.) 



the other workers. I have found such workers in nests of Formica 

 rufibarbis, F. fusca v. rubescens, species of Leptothorax, etc. 



26. The phthisergate corresponds to the phthisaner and phthiso- 

 gyne, and arises from the same causes. 



27. The dichthadiigyne, or dichthadiiform female, is peculiar to 

 the Dorylinae, and of course is not found in Britain. It is without 

 eyes, ocelli, or wings, and is probably a further development of 

 the gynaecoid worker. 



28. The desmergate is an intermediate form between the soldier 

 and the typical worker. Wheeler suggests that the term might 

 also be employed to designate the intermediate forms between the 

 small and large workers in such genera as Monomorium, Formica, 



