164 FORMICID^ — ANTS. 



insects, and wliose observations can be most relied on, has 

 made us lu-qnainted with two of their maladies: one is a 

 speeies of verti<z:o, occasioned, as he thinks, by a too ^reat 

 heat of the sun, and which transforms them for two or three 

 minutes into a sort of bacchantes; the other malady, much 

 more severe, causes them to lose the faculty of directing 

 themselves in a ri<;ht line. These Ants turn in a very nar- 

 row circle, and always in the same direction. A virgin 

 female, inclosed in a sand-box, and attacked by this mania, 

 made a thousand turns by the hour, describing a circle of 

 about an inch in diameter ; it continued this operation for 

 seven days, and even during the night.^ 



Immense swarms of winged Ants are occasionally met 

 with, and some have been recorded of such prodigious den- 

 sity and magnitude as to darken the air like a thick cloud, 

 and to cover the ground or water for a considerable extent 

 where they settled. We find in the memoirs of the Berlin 

 Academy a description of a remarkable swarm, observed by 

 M. Gleditch, which from afar produced an effect somewhat 

 similar to that of an Aurora Borealis, when, from the edge 

 of the cloud, shoot forth by jets many columns of flame and 

 vapor, many rays like lightning, but without its brilliancy. 

 Columns of Ants were coming and going here and there, 

 but always rising upward, with inconceivable rapidity. They 

 appeared to raise themselves above the clouds, to thicken 

 there, and become more and more obscure. Other columns 

 followed the preceding, raised themselves in like manner, 

 shooting forth many times with equal swiftness, or mounting 

 one after the other. Each column resembled a very slender 

 net-work, and exhibited a tremulous, undulating, and ser- 

 pentine motion. It was composed of an innumerable mul- 

 titude of little winged insects, altogether black, w^hich were 

 continually ascending and descending in an irregular man- 

 ner.^ A similar kind of Ants is spoken of by Mr. Acco- 

 lutte, a clergyman of Breslau, which resembled columns of 

 smoke, and which fell on the churches and tops of the 

 houses, where they could be gathered by handfuls. In the 

 German Epheme rides, Dr. Chas. Rayger gives an account 

 of a large swarm which crossed over the town of Posen, and 

 was directing; its course toward the Danube. The whole 



^ Cuv. An. Kingd. — Ins., ii. 47: 

 2 Mem. Berlin Acad, for 1749. 



