164 



HYMENOPTERA 



CHAP. 



individuals weigh 1 gramme, and it is probable that a nest 



may include millions of specimens. 



The genus Aphaenogaster^ and its immediate- allies include the 



harvesting ants of Europe and North America : they form subter- 



ranean nests consisting of iso- 

 lated chambers connected by 

 galleries ; some of the chambers 

 are used as store -houses or 

 granaries, considerable quantities 

 of corn, grass, and other seeds 

 being placed in them. A. 

 structor and A. lar/i/i/'//* have 

 been observed to do this in 

 Southern Europe by Lespes, 

 Moggridge, and others. 



In the deserts about Algeria 

 and Tunis a harvesting ant, 

 Aphaenogaster (Messor) aren- 

 arius, is an important creature : 

 its subterranean dwellings are 

 very extensive, and are placed 

 at a depth of several feet from 

 the surface. Entrance to these 

 dwellings is obtained by small 



holes, which are the orifices of 

 Flu. 70. Aphaenogaster (Messor) barbarus. , , , 



Algeria. A, male ; B, winged female : galleries many feet in length : 



C, large worker or soldier; D, small 

 worker, x -I}. 



the holes are SUlTOimded by 



. . 



pellets ot sand projecting some- 

 what above the general surface, and consequently making the 

 places conspicuous. The subterranean works occupy an area of 

 iifty or a hundred square yards excavated at a depth of three to 

 six feet. In these immense nests there exists a form of worker, 

 of very small size, that never conies to the surface. 2 



Pogonomyrmex l><irl><itns and other species have been observed 

 to do harvesting in North America. After the workers of P. 

 !>/ 1, -I in Ins have taken the seeds into the nest they separate the 

 husks and carry them out, depositing them on a heap or kitchen- 



1 Until I'crcully this genus was generally known as Atta, but this name is now 

 applied to the leai'-futting ants, that were formerly called Oeeodoma. 



2 Foivl, /;,///. Soc. Vaudoise, xxx. pp. 29-30, 1S91. 



