SANITATION PERSONAL BENEVOLENCE 



of the mound. Moreover, there is an extensive system 

 of underground galleries reaching, in one case at least, 

 sixty feet from the central mound, and these are prob- 

 ably ventilated through the basal gates. But it is not 

 so easy to see how such vast structures as the nests of 

 the agricultural and Occident ants can be ventilated 

 through their single gates. 



The problem of drainage must be a pressing one in 

 ant communes, and its practical solution is an interest- 

 ing study, although one must depend more upon reason- 

 able inference than deduction from known facts. That 

 many nests must be inundated during long and hard 

 rains is inevitable. That their inmates can endure 

 a goodly period of submerging without drowning is 

 known. But some method of warding off or carrying 

 off or absorbing the excess of water in severe rains and 

 floods seems to be required. 



The conical shape of such nests as are built by mound- 

 making, Occident, and rufous ants, although perhaps pri- 

 marily due simply to the natural action of gravitation, 

 must aid in keeping the inmates dry by shedding the 

 rains as do our own peaked house-roofs. One would 

 think that placing the bulk of the gates near the base of 

 the mound would be disadvantageous until he remem- 

 bers that the large space above, with its numerous series 

 of interlacing galleries and rooms, gives an admirable 

 refuge for the commune's infant charges. There they 

 may be deported in heavy rains and kept in good con- 

 dition. 



In the case of such single-gated cones as those of the 

 Occident ants, the danger of flooding is less; and, more- 

 over, there, as with the flat disks of the agricultural ant, 

 gate-closing can be resorted to. At least one example 



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