208 



ANTS. 



ill cavities that have been wholly or in part excavated by wood-destroy- 

 ing larv;e, beetles, etc. A iiuniber of species which live in small colo- 

 nies have learned to take advantage of .Mich cavities in the bark of trees, 

 in twigs, woody galK etc. These cavities may be modified and extended 

 to >uit the convenience of the ants. Some of our species of Lcpto- 

 tlioni.r ( cdiHitlcnsis. scliaiiini. fortinodis) prefer the cork-like bark of 

 dead or living irce-trnnk.s, our Colohopsis species and numerous varie- 

 ties of the circumpolar Camponotus falla.v inhabit the solid wood 

 <>f hickory, pine or oak twigs 3 to 4 cm. in diameter. The dead wood 



FIG. 1 13. Gall of Hol- 

 caspis cinerosiis inhabited 

 by colony of Leptothorax 

 obturator. (Original.) The 

 large opening through 

 which the gall fly escaped 

 has been plugged with car- 

 ton by the Leptothorax 

 queen and subsequently 

 perforated by her workers 

 to form the permanent 

 entrance. 



FIG. 114. Ends of broken 

 twigs of Sea-grape (Coccoloba 

 urifcra) showing carton dia- 

 phragms of Camponotus sc.rgul- 

 tatus. with circular entrances. 

 (Original.) a. With a flat. b. 

 with a cone-shaped diaphragm, 

 the latter being an adaptation to 

 the oblique fracture of the hol- 

 low twig. 



of standing or prostrate trunks is often extensively riddled by the 

 galleries of Crcinastogastcr lincolata and Camponotus pennsylvani- 

 cus, noveboracensis, ferrugineus, and levigatus. These insects, which 

 are popularly known as carpenter ants, apparently start their intricate 

 galleries in spots where the wood has decayed or has been in part de- 

 stroyed by other insects. The galleries are often continued down into 

 the underlying soil, especially in arid regions where the wood dries out 

 in summer. 



In some parts of the country the old woody galls on oaks furnish 

 the ants with exceptionally convenient quarters in which to start colo- 

 nies or even for the permanent accommodation of small communities. 

 This is especially true of the galls of a Cynipid (Hoi cassis cinerosiis'} 

 on the live-oaks of central Texas. These spherical galls, which measure 

 from 2-4 cm. in diameter, after being deserted by the insects that pro- 

 duce them, remain attached to the twisfs for several vears. Much of 



