138 The Naturalist in La Plata. 



insects have certainly had ample time in which to 

 learn well at least one lesson. 



There is not in all organic nature, to my mind, 

 any instance of wasted energy comparable in 

 magnitude with the mosquito's thirst for blood, and 

 the instincts and elaborate blood-pumping apparatus 

 with which it is related. The amount of pollen 

 given off by some wind-fertilized trees — so great in 

 some places that it covers hundreds of square miles 

 of earth and water with a film of yellow dust — 

 strikes us as an amazing waste of material on the 

 part of nature ; but in these cases we readily see 

 that this excessive prodigality is necessary to con- 

 tinue the species, aad that a sufficient number of 

 flowers would not be impregnated unless the entire 

 trees were bathed for days in the fertilizing cloud, 

 in which only one out of many millions of floating 

 particles can ever hit the mark. The mosquito is 

 able to procreate without ever satisfying its ravenous 

 appetite for blood. To swell its grey thread-like 

 abdomen to a coral bead is a delight to the insect, 

 but not necessary to its existence, like food and 

 water to ours ; it is the great prize in the lottery 

 of life, which few can ever succeed in drawing. In 

 a hot summer, when one has ridden perhaps for 

 half a day over a low-lying or wet district, through 

 an atmosphere literally obscured with a fog of 

 mosquitoes, this fact strikes the mind very forcibly, 

 for in such places it frequently is the case that 

 mammals do not exist, or are exceedingly rare. In 

 Europe it is different. There, as Reaumur said, 

 possibly one gnat in every hundred may be able to 



