138 LIVING FISHFOODS 



sheet of glass, leaving about two inches at one end not covered. Over 

 this open space place a piece of mosquito netting, drawing it up several 

 inches over the opening into a sort of inverted bag. Then draw a string 

 around top edge of tank to fasten netting down. As the mosquitoes 

 hatch they will fly upward into the netting bag, where they may be 

 mashed before lifting the lid to get larvje for the fish. The author 

 usually keeps these larv;e in a 5-gallon drinking water bottle, half 

 filled, and with a bit of netting over the top, secured by a rubber 

 band. To use larvs, remove netting, place hand over opening and 

 quickly invert bottle. The larvse in their excitement swim downwards 

 into neck of bottle. Release hand and empty the required quantity. 

 Replace netting and add water to make up to former level. When 

 most of the larvae have been used and a number of mosquitoes remain 

 in the bottle, fill with water (through the netting) and they will be 

 drowned. A netting bag trap secured on neck of bottle will also catch 

 the majority of the mosquitoes. 



The larvffi should be kept out of the sun and in as cool a situation 

 as possible so as to retard the hatching of larvs into mosquitoes. 

 They will stand great crowding, their only requirement being that 

 there is room for them all to get to the surface at one time, for they 

 breathe air. This is one advantage in placing larvae with fish, for, un- 

 like daphnia, they extract no oxygen from the water. By feeding them 

 to the fish we not only do well for the fish, but serve the interests 

 of humanity by cutting down the mosquito pest. In open pools gold- 

 fishes are one of the best agents in keeping the neighborhood free of 

 mosquitoes. Unfortunately the mosquito larv^ can live and hatch 

 in temporary pools and in water too foul for any fish to survive in. 



Cypris. Incorrectly known as "hardshell daphnia," cypris forms an 

 important article of fish diet. These Crustacea inhabit stangnant pools, 

 particularly those well stocked with decomposing vegetal matter. 

 Although capable of swimming freely they are more apt to remain close 

 to the bottom, but more especially to decaying wood. They are of a dull, 

 purplish black or reddish color about the size of an ordinary pin-head. 

 Inexperienced observers frequently mistake them for daphnia. Fishes 

 do not appear to be quite so fond of them as of daphnia, but they are a 

 good second choice. They are extremely hardy and will withstand dense 

 overcrowding in the foulest of water. Under favorable conditions cypris 

 multiplies with astounding rapidity. It has been claimed that they 

 devour spawn and young fishes. This is undoubtedly an error, but 

 they do greatly annoy snails and eventually cause their death by get- 

 ting into some inner recesses of the animal. 



