136 The Naturalist in La Plata. 



said, sheltering themselves wherever trees occur ; 

 and, after the storm blows over, these strangers 

 and stragglers remain for some days hawking for 

 prey in the neighbourhood. It is curious to note 

 that they do not show any disposition to seek for 

 watercourses. It may be that they feel lost in a 

 strange region, or that the panic they have suffered, 

 in their long flight before the wind, has unsettled 

 their instincts ; for it is certain that they do not, 

 like the dragon-fly in Mrs. Browning's poem, " re- 

 turn to dream upon the river." They lead instead 

 a kind of vagabond existence, hanging about the 

 plantations, and roaming over the surrounding 

 plains. It is then remarked that gnats and sand- 

 flies apparently cease to exist, even in places where 

 they have been most abundant. They have not 

 been devoured by the dragon-flies, which are perhaps 

 very few in number ; they have simply got out of 

 the way, and will remain in close concealment until 

 their enemies take their departure, or have all been 

 devoured by martins, tyrant birds, and the big 

 robber-flies or devil's dykes — no name is bad enough 

 for them — of the family Asilidse. During these 

 peaceful gnatless days, if a person thrusts himself 

 into the bushes or herbage in some dark sheltered 

 place, he will soon begin to hear the thin familiar 

 • sounds, as of " horns of elf-land faintly blowing "; 

 and presently, from the ground and the under 

 surface of every leaf, the ghost-like withered little 

 starvelings will appear in scores and in hundreds 

 to settle on him, fear not having blunted their keen 

 appetites. 



When riding over the pampas on a hot still day, 



