MOTIONS OF INSECTS. 517 



have often mentioned ; — it seems the merriest and most agile of all the 

 inhabitants of the waves. Wonderful is the velocity with which they 

 turn round and round, as it were pursuing each other in incessant circles, 

 sometimes moving in oblique, and indeed in every other direction. Now 

 and then they repose on the surface, as if fatigued with their dances, and 

 desirous of enjoying the full effect of the sun-beam: if you approach the)k 

 are instantaneously in motion again. Attempt to entrap them with your 

 net, and they are under the water and dispersed in a moment. When 

 the danger ceases they reappear, and resume their vagaries. Covered 

 with lucid armor, when the sun shines they look like little dancing masses 

 of silver or brilliant pearls.^ 



But the motions of this kind to which I particularly wish to call your 

 attention are the choral dances of males in the air ; for the dancing sex 

 amongst insects is the masculine, the ladies generally keeping themselves 

 quiet at home. These dances occur at all seasons of the year, both in 

 winter and summer, though in the former season they are confined 

 to the hardy Tipulariae. In the morning before twelve, the HoplicE, root- 

 beetles before mentioned, have their dances in the air, and the solstitial 

 and common cockchafer appear in the evening — the former generally 

 coming forth at the summer solstice — and fill the air over the trees and 

 hedges with their myriads and their hum. Other dancing insects resem- 

 ble moving columns — each individual rising and falling in a vertical line 

 a certain space, and which will follow the passing traveler — often intent 

 upon other business, and all unconscious of his aerial companions — for a 

 considerable distance. 



Towards sunset the common Ephemerae (^E. vulgata), distinguished by 

 their spotted wings and three long tails (caudulce), commence their dances 

 in the meadows near the rivers. They assemble in troops, consisting 

 sometimes of several hundreds, and keep rising and falling continually, 

 usually over some high tree. They rise beating the air rapidly with their 

 wings, till they have ascended five or six feet above the tree ; when they 

 descend to it with their wings extended and motionless, sailing like hawks, 

 and having their three tails elevated, and the lateral ones so separated as 

 to form nearly a right angle with the central one. These tails seem 

 given them to balance their bodies when they descend, which they do in 

 a horizontal position. This motion continues two or three hours without 

 ceasing, and commences in fine clear weather about an hour before sun- 

 set, lasting till the copious falling of the dew compels them to retire to 

 their nocturnal station." Our most common species, which I have usually 

 taken for the E. vulgata, varies from that of De Geer in its proceedings. 

 I found them at the end of May dancing over the meadows, not over the 

 trees, at a much earlier hour — at half-past three — rising in the way just 

 described, about a foot, and then descending, at the distance of about 

 four or five feet from the ground. Another species, common here, rises 

 seven or eight feet. I have also seen Ephemerae flying over the water in 



' Compare Oliv. Eatomol. iii. Gyrinus 4. One speices, however, Gyrinus (Orechtocheilus) 

 villosus, which, as before observed, pursues its dances only at night, differs also from its 

 congeners in not having the same habit of diving, or at least not in the daytime, when, if 

 forced inio the water from its hiding-places under stones, all its efforts are confined to en- 

 deavoring to regain the shore. (Ann. Soc. Ent. de France, iv. bull. Ixxx.) 



« De Geer, ii. 638. 



44 



