CHAPTER X 



OBSERVATIONS ON INSECT LIFE 



Mountain dust — Inhabitants of pools^Carnivorous flies — Water-boatmen 

 — Struggle for life — Mentality of fishes — Habits of Vespa orientalis 

 — Nest of Polistes — Depredations of Vespa juagnifua -Mimicry in 

 humble-bees — Humble-bees and flowers — Habits of leaf-cutting 

 bees — Instinct of mud-wasp — Instinct of digger-wasps. 



Temperature and season greatly influence the aspect 

 of a country. They are the common agents of 

 physical change. Their action in this valley presents 

 one feature deserving of our notice : the cloud of 

 fine dust that daily fills the sky. In the oppressive 

 days of summer, when for weeks no rain may fall, 

 a dense haze collects over the mountains. It hangs 

 thick over the valleys, and, like a veil, envelops even 

 the highest peaks. The burning cliffs radiate a fierce 

 heat and there is scarce a movement in the breathless 

 air. All objects are obscured as though in a dim mist. 

 The trees are unreal ; the hills are ill-defined ; they 

 look bleak and uninviting, as though we looked 

 through a moist fog on to a rocky shore. From a 

 summit we obtain no sight of a distant range, and the 

 plains are concealed beneath a shroud of dust. The 

 atmosphere looks polluted, foul and murky, a vision of 

 discomfort. Sickness increases. All vitality is lost 

 when the cloud of heat obscures the sky. This haze 

 is due to the permeation of the atmosphere with a very 

 fine dust carried up by ascending convection currents 



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