'38 ON ENTOMOLOGY. 



Ant-hill. The ground floor becoming- in its turn uninhabitable during 

 the rainy season, the Ants of this species transport what most interests 

 them to the higher stories, and it is there they are found more usually 

 assembled with their eggs and pupse, when the subterranean apart- 

 ments are submerged. Ants have a great dislike to water w T hen it ex- 

 ceeds that of a light shower to moisten their building materials. One 

 species, mentioned by De Azara, as indigenous to South America, in- 

 stinctively builds a nest from three to six feet high to provide against 

 the inundations during the rainy season. Even this, however, does not 

 always save them from submersion ; and when that occurs, they are 

 compelled, in order to prevent themselves from being swept away, to 

 form a group somewhat similar to the curtain of the wax-workers of 

 Jliue-bees. The Ants constituting the basis of this group lay hold of 

 some shrub for security, while their companions hold on by them, and 

 thus the whole colony, forming an animated raft, floats on the surface of 

 the water till the inundation (which seldom continues longer than a day 

 or two) subsides. 



It is usual with architectural insects to employ some animal secretion 

 by way of mortar or size to temper the materials with which they work, 

 but the whole economy of Ants is so different, that it would be wrong to 

 infer from analogy a similarity in this respect, though the exquisite 

 polish and extreme delicacy of finish in their structures lead naturally 

 to such a conclusion. Huber, in order to resolve this question, at first 

 thought of subjecting the materials of the walls to chemical analysis, 

 but wisely abandoned it for the surer method of observation. The de- 

 tails which he has given as the result of his researches are exceedingly 

 curious and instructive. IJe began by observing an Ant-hill till he 

 could perceive some change in its form. The inhabitants, says he, of 

 that which I selected, kept within during the day, or only went out by 

 subterranean galleries which opened at some feet distance in the meadow. 

 There were, however, two or three small openings on the surface of the 

 nest, but I saw none of the labourers pass out this way on account of 

 their being too much exposed to the sun, which these insects greatly 

 dread. This Ant-hill, which had a round form, rose in the grass at the 

 border of a path, and had sustained no injury. 1 soon perceived that the 

 freshness of the air and the dew invited the Ants to walk over the sur- 

 face of their nest ; they began by making new apertures : several of the 

 Ants might be seen arriving at the same time, thrusting their heads from 

 the entrances, and at length adventuring forth to visit the environs. 

 This brought to my recollection a singular opinion of the ancients. They 

 believed that Ants were occupied in their architectural labours during 

 the night when the moon was at its full. Having noticed the movements 

 of these insects during the night, I found they were always abroad and 

 engaged about the dome of their habitation after sunset. This was 

 directly the reverse of what I had observed in the conduct of the \Voml 

 Ants (Formica rnfu), who only go out during the day, and close their 



