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 wdll 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, 
