44 



few gobies, locally known as "oopii,'' the gold fish are the only fish 

 in Hawaii that are especially fond of the mosquito wriggler. An 

 attempt will be made to introduce into the islands fish that are special 

 mosquito feeders. 



INTRODUCTION OF MOSQUITO- EATING FISH. 



Several years ago the entomologist concluded that the absence of 

 special mosquito-feeding fish was responsible for the numl)ers of mos- 

 quitoes which must be credited as breeding in taro patches, rice fields, 

 irrigation ditches, lily ponds, and especially the abandoned rice and 

 taro fields. The following letter, self-explanatory, was addressed to 



Doctor Jordan : 



January 9, 1903. 

 Dr. David Starr Jordan, 



President Leland Stanford, jr., University, 



Stanford University, Col. 



My Dear Doctor Jordan: I am working just now on the mosquito problem here. 

 In regard to the natural enemies of this pest, I would like to find out what fish or 

 fishes we have here in the small ponds, streams, taro patches, and rice fields (the 

 natural breeding places of the mosquito) which feed to any extent on the larva? and 

 pup£e. The common "gold fish" occurs here in large numbers, and, I lielieve, feeds 

 to a great extent on the young mosquitoes. I have observed a single fish eat nearly 

 two hundred larvai during two days' confinement in an aquarium. Other gold fish 

 taken from small pools contained the remains of larvfe in their stomachs. 



Doctor Howard speaks of the common sunfish and one or two species of "top 

 minnows" as especially active in the destruction of mosquito larvte and pupa^. 

 Would it not be feasible for us to attempt to introduce some of these beneficial species 

 to breed in places where it is undesirable to drain or use the oil treatment? 



Verv sincerely, yours, • -r. x ^^ -r^ 



D. L. \ an Dine. 



Doctor Jordan replied as follows: 



Stanford Univer-sity, Cal., Jamiary^i, iPO-S. 

 Mr. D. L. Van Dine, 



Experiment Station, Honolidu, Hawaii. 



Dear Sir: The only fishes that you have which feed upon mosquitoes in the small 

 ponds are the different kinds of gobies, locally known as "oopu," and the gold fish. 

 The different species of oopu are found in all the streams, but whether they feed on 

 the larvfe or not must be determined by dissection. 



The top minnows are entirely unrepresented in Hawaii. They are very easily 

 transported, being extremely hardy. There are, however, none of them in Cali- 

 fornia, and they would have to be brought either from the ^Mississippi Valley or from 

 Mexico. The best species for your purpose could be found in the streams of central 

 Mexico, but it would be a little costly to send a man down to get them. Next to 

 these I would recommend trying the Gulf States or Florida. These species belong 

 to the family of PoeciUida;, and there are many species, nearly all American. The 

 single Japanese species is common in rice ditches in the extreme south of Japan, and 

 probably feeds on larvte. 



Very truly, yours, David S. Jordan. 



While Doctor Jordan was in Honolulu recently the subject was 

 further discussed, and he ottered to send an e.xpert of Stanford Uni- 



