PERFECT SOCIETIES OF INSECTS. 317 



observe the troop defile before them ; traversing its ranks ; hastening to 

 any point where their presence seems necessary, especially if it have met 

 with any obstacle on its route ; and even climbing, as M. Lacordaire has 

 often witnessed, up the adjoining plants, and perched on the margin of a 

 leaf, surveying its passage from this elevated position. 1 M. Lund observed 

 four of these large-headed neuters of a Brazilian species of Myrmica to 

 guard the entrance to their nest, and others attending the column while on 

 march, and hastening to the spot and alarming their comrades when some 

 of the ants were purposely killed. 2 



An equally singular modification of form and function takes place in the 

 neuters of a Mexican ant Myrmecocystus Mexicanus of M. Wesmael, 

 who has described their economy in a paper read to the Academic Royale 

 of Brussels. Of this species, while some of the neuters have the ordinary 

 form, others, which never quit the nest and are almost inactive, have their 

 abdomen swollen into an immense subdiaphanous sphere, filled by a kind 

 of honey which they are solely occupied in elaborating, and which they 

 subsequently discharge into cells analogous to those of bees. 3 



Having introduced you to the individuals of which the associations of 

 ants consist, I shall now advert to the principal events of their history, re- 

 lating first the fates of the males and females. In the warm days that occur 

 from the end of July to the beginning of September, and sometimes later, 

 the habitations of the various species of ants may be seen to swarrn with 

 winged insects, which are the males and females preparing to quit for ever 

 the scene of their nativity and education. Every thing is in motion ; and 

 the silver wings, contrasted with the jet bodies which compose the animated 

 mass, add a degree of splendour to the interesting scene. The bustle in- 

 creases, till at length the males rise, as it were by a general impulse, into 

 the air, and the females accompany them. The whole swarm alternately 

 rises and falls with a slow movement to the height of about ten feet, the 

 males flying obliquely with a rapid zigzag motion, and the females, though 

 they follow the general movement of the column, appearing suspended in 

 the air, like balloons, seemingly with no individual motion, and having their 

 heads turned towards the wind. 



Sometimes the swarms of a whole district unite their infinite myriads, 

 and, seen at a distance, produce an effect resembling the flashing of an 

 aurora-borealis. Rising with incredible velocity in distinct columns, they 

 soar above the clouds. Each column looks like a kind of slender net-work, 

 and has a tremulous undulating motion, which has been observed to be 

 produced by the regular alternate rising and falling just alluded to. The 

 noise emitted by myriads and myriads of these creatures does not exceed 

 the hum of a single wasp. The slightest zephyr disperses them ; and if in 

 their progress they chance to be over your head, if you walk slowly on 

 they will accompany you, and regulate their motions by yours. The females 

 continue sailing majestically in the centre of these numberless males, who 

 are all candidates for their favour, each till some fortunate lover darts upon 

 her, and, as the Roman youth did the 'Sabine virgins, drags his bride from 

 the sportive crowd, and the nuptials are consummated in mid-air; though 

 sometimes the union takes place on the summit of plants, but rarely in the 



* Lacordaire, Introd. a VEntom. ii. 498. 



2 Lund in Ann. des Sciences Nat. xxiii. 113. ; quoted by Lacordaire, uU supr., and 

 Westwood, Mod. Class, ii. 225. 

 5 Bull. Acad. Roy. Bruxell. v. 771. ; quoted by Westwood, ubi supr. ii. 225. 



