ntmmmtim. ^ij^ _^^ 



Photo by the Auth( 



NEST OF THE OCCIDENT ANT {Pogonoifiyrmex occid entails) which buieds 



INCUBATORS FOR ITS YOUNG 



On the Dry Plains at Las Vegas, New Mexico. The nest cone has its entrance near 

 the base and nearly always on the east or sovith side. It is closed at night by the workers, 

 and the advantage of having it in this position is to insure its being opened earlier in the 

 morning when the warmth of the sun awakens the workers (see text, pages 746 and 747)- 



DIAGRAMS OF THREE STAGES IN THE DEVELOPMENT OF THE NEST-MOUNT OF THE 



OCCIDENT ANT {Pogofiomyrmex occidentalis) which builds 



INCUBATORS FOR ITS YOUNG 



A, small mound of earth thrown up by the queen when startmg her formicary; x, en- 

 trance; 2, first chamber; A', same nest in section; B, crater nest (second year) formed by 

 incipient colony; B', section of same; C, dome of adult colony; C, section of same showing 

 -galleries and chambers used for incubation of the young (see text, pages 746 and 747). 



759 



