In this case the total period was about eleven days. On the twelfth 

 day the basin was ready for another dose of skim milk. 



In all cases where the dosage was increased beyond 1 pint per 

 10 cubic feet of water every other day for 5 days, there was a per- 

 ceptible odor not at all agreeable. The resting period tended to pre- 

 vent bad odors. If the production were undertaken on a larger scale 

 one would presume that bad odors would be more in evidence even 

 with the dosage mentioned above. 



It was stated that two species of mosquitoes appeared abundantly 

 in the ponds. These were Culex sexatilis and C. territans. The 

 former is reported as not biting man but the latter is considered a 

 pest in many places. However this may be, it can be stated posi- 

 tively that during the two summers that this work has been going on 

 and many thousands of mosquitoes have been allowed to reach the 

 adult stage, no one living or working on the hatchery grounds has 

 been pestered by them day or night. 



There is no need of allowing the mosquitoes to reach the biting 

 stage, if they are collected and fed to fish at the proper time. It is 

 very easy to observe the first mosquitoes reaching the pupal stage 

 and if the pond is drawn off or if it is swept carefully with a net of 

 fine-meshed bobbinet, the mosquitoes can be disposed of to the fish 

 before they are ready to transform. 



There are two possible advantages in using the net. One may 

 have a fairly continuous supply of larvae by allowing the small ones 

 just hatched to pass through the meshes of the net. These will grow 

 and can be captured the next few days. The other advantage is that 

 no pollution is allowed to enter the fish pond. 



Bass and trout will eat large quantities of mosquitoes with appar- 

 ent relish. The rate of growth in the case of the trout seems to be as 

 rapid as with any other food tried by us. The mosquitoes are 

 especially useful as a supplement to those food mixtures consisting 

 of dried meat, fish, and clam and shrimp meal. Certain health and 

 growth-promoting substances called vitamines are absent or else 

 occur in insufficient amounts in these meals, and consequently by 

 their continuous and sole use food-deficiency diseases appear in trout. 

 It has been found that when live mosquito larvae are fed with the 

 dry meals not only is the mortality lowered but the rate of growth is 

 increased. 



OTHER FOOD ANIMALS PRODUCED 



The rat-tail maggots and tubifex worms occurred in the earth and 

 cement ponds and in the wood troughs. They were abundant when 

 a high dosage was used. Neither form, however, appeared in such 



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