EXPERIMENT STATION BULLETINS. 



137 



eral open ponds having considerable depth were stocked with these 

 fish, and very good results were obtained, the sun-fish, indeed, seeminjg 

 to have an almost insatiable desire for the wigglers. The stickle-backs 

 also did very well. Another small fish known as the mud-minnow did 

 good service in shallow pools where either of the other fish would have 

 found it impossible to live. 



The season 'has been extremely wet in Michigan and for this reason 

 it is impossible to judge of the benefit received from this treatment. 

 Rain fell at short intervals so that, in many places, pools remained all 

 summer where ordinarily they dried up in June. The grass has been 

 almost constantly wet, a condition very favorable to mosquito life, and 

 while many millions have been killed, many have drifted in from out- 

 side. Mosquitoes were plentiful enough it is true. We can imagine 

 how numerous they would have been if the many millions which were 

 killed had been left to live. 



i'ig.SJ. —Mosquitoes killed by disease, nat. size, original. 

 DISEASE OF THE MOSQUITO. 



On August 5th Mr. Barlow brought in a number of mosquitoes killed 

 by a fungus {Entomophthora sp. nov.). They were very numerous on 

 the margins of one of the pools in woodland, sometimes almost cover- 

 ing the pieces of bark to which they clung. In typical cases they were 

 covered with a dense white growth, all were within a few inches of the 

 water. This fungus was also found on several other species of flies 

 and on a dragon-fly. All attempts to grow the fungus in the labora- 

 tory were futile. The disease was, however, spread in one instance by 

 distributing pieces of bark covered with the dead insects into fresh 

 colonies. It is not likely that this disease will ever prove to be very 

 helpful. It may reduce the numbers of the pests but it will never erad 

 icate them, and like most diseases, it works best when the victims are 

 in the greatest numbers. 

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