BAHIA HONDA TO CABANAS 295 



carrying insects. There are, however, a vast 

 number of species of mosquitoes of unknown habit, 

 except possibly by inference. Generalizations 

 therefore may be dangerous, but from all observa- 

 tions so far made it would appear that the blood- 

 sucking habit is an acquired one, the natural food 

 being, or having been in the past, the juices of 

 plants and fruits. Any liquid containing organic 

 matter is acceptable. The exudation from animal 

 wounds, with its slightly sweetish serum, probably 

 offered to these ravenous insects their first step 

 toward blood-sucking. The highly organized ap- 

 paratus, especially of the female, for puncturing 

 leaves, needed but slight modification for becom- 

 ing a most perfect surgical instrument for tapping 

 the skin of animals for their blood. It seems also 

 to be true that the habit of blood-sucking is con- 

 fined almost wholly to the females, for they have 

 now become dependent upon a supply of blood for 

 the nutriment, not so much of themselves, as of 

 the eggs developing within their bodies. Without 

 such supply their eggs will not mature to the point 

 necessary for oviposit. This very special habit of 

 the females has naturally developed their organs 

 for getting blood to a degree far beyond those 



