98 Insects and Disease 



forded in the introduction of mosquitoes into 

 Hawaii. Up to 1826 there were no mosquitoes on 

 these islands. It is supposed that they were intro- 

 duced about that time by some ships that were 

 trading at the islands. Indeed it is claimed that 

 the very ship is known that brought them over 

 from Mexico. 



Once introduced they found conditions there 

 very favorable to their development, plenty of 

 standing water and few natural enemies to prey on 

 them, so they increased very rapidly and gradually 

 spread over all the islands of the group. This was 

 the so-called night mosquito, Culex pipiens. Much 

 later another species, Stegomyia calopus, just as 

 annoying and much more dangerous was intro- 

 duced and has also become very troublesome. We 

 have a few species of top-minnows (Fig. 88) occur- 

 ring in sluggish streams in the southern part of the 

 United States that are important enemies of the 

 mosquitoes of that region. A few years ago some 

 of these were taken over to Hawaii and liberated 

 in suitable places to see if they would not help solve 

 the mosquito problem there. The fishes seem to be 

 doing well. Already they are destroying many 

 mosquito larvae, and there are indications that they 

 are going to do an important work, but of course 

 can be depended on only as an aid. 



