POLYMORPHISM. 1 '3 



really micrergates. This condition is seen in certain Myrmicine genera, 

 especially of the tribe Solenopsidii (Carcbara, Erebouiynna, Diplo- 

 inoriiiin, most species of Solenopsis, etc.). 



5. The worker form disappears completely leaving only the males 

 and females to represent the species, which thus returns to the con- 

 dition of sexual dimorphism seen in the great majority of insects and 

 other Metazoa. This occurs in the parasitic ants of the genera 

 Ancryatcs, H'licelcrieila, Eptrcus, Sympheidole and Epiphcidolc. 



6. In certain species the workers remain stationary while the 

 female increases in size. This is indicated by the fact that the worker 

 and male have approximately the same stature. Such a condition ob- 

 tains in certain Myrmicinae (Crcuiastogastcr), Camponotinae (Lasius, 

 Prenolepis, Brachymyrmex , North American species of ^l\rmccoc\s- 

 tits) and Dolichoderinse (Iridoiuynnc.r, Doryinynnc.r, Lioinctopuin ) . 



7 '. The worker caste remains stationary while the female diminishes 

 in size till it may become even smaller than the large workers. This 

 occurs in certain parasitic species of North America, like Aphtcno- 

 i/astcr tcniicsseensis among the Myrmicinae, and among the Campono- 

 tinae in the species of the Formica microgyna group ( F. difficiiis, 

 nci'adcnsis, iinpc.va, dakotcnsis, ncpticula). 



8. The female phase disappears completely and is replaced by a 

 fertile, or gynsecoicl worker form. This occurs in certain Ponerine 

 genera like Lcptogcnys (including the subgenus Lobopelta), and prob- 

 ably also in Diacainina and Champ somyrmex. The conditions in 

 Acanthostichus and certain Cerapachysii ( Parasyscia peringueyi ) indi- 

 cate that the dichthadiigynes of the Dorylinae may have arisen from 

 such gynsecoid workers instead of from winged queens. 



9. The female shows a differentiation into two forms (a- and /8- fe- 

 males ) characterized by differences in the structure of the legs and 

 antennae, in pilosity and coloration (Lasins latipes), or in the length of 

 the wings ( macropterous and micropterous females of L. nigcr). 

 The macrocephalic and microcephalic females of Camponotus abdoini- 

 nctlis and confusns described by Emery ( 1896^) may also be regarded 

 as r t- and /2-forms. 



In this series of stages, one to five represent changes in the worker 

 caste while the female remains relatively stationary, whereas stages 

 six to nine represent the converse conditions. Stages one to four 

 probably succeeded one another in the order given, but stage five may 

 have arisen either from the first or fourth. The sixth to ninth stages 

 must, of course, be supposed to have developed independently of one 

 another. 



The stature differences described in the above paragraphs are, in 



9 



