TROPICAL AQUARIUM FISHES 133 
practically worldwide in distribution. The two tabs seen near the lower 
portion of the illustration are the egg-pouches of the female. These 
develop in warm weather every two days, become detached and fall to 
the bottom with 16 to 32 eggs which arrive at maturity in 30 days. They 
are called Cyclops because, like the giant of mythology, they have but 
one eye. 
Mosquito Larve. These are often known as wrigglers and are 
familiar to those who have looked in rain barrels. Their bodies are 
straight and about a quarter of an inch long. They rest at an angle to 
the surface of the water as shown in Fig. 84, with head down, and are 
always ready to “wriggle” to the bottom at the first sign of danger. 
From midsummer on they may be found in still water where there are 
no fish. They are taken in the same manner as daphnia, except that 
one has to get them with a quick sweep before they can get down into 
the water. They can usually be seen floating together in black masses. 
The city entomologist anywhere will give information as to where they 
may be obtained and will be glad to have his burdens lightened by the 
fish breeder. 
Mosquito Larve may be termed a special food. It can only be 
had in large quantities towards the middle and end of Summer, and is 
only suited to the fish large enough to easily swallow it. As a food for 
putting growth on fish an inch long or over it has no equal. The main 
drawback to these larve is that those not eaten quickly by the fish are 
liable to turn to mosquitoes. This difficulty can be discounted by proper 
management. Keep the stock of larve in a tank covered by a 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 killed 
before lifting the lid to get larvee for the fish. The larvae should be kept 
out of the sun and as cool as possible so as to retard hatching. 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 larve with fish, for, unlike 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 goldfishes are one of the best 
agents in keeping the neighborhood free of mosquitoes. Unfortunately 
the mosquito larve can live and hatch in temporary pools and in water 
too foul for any fish to survive in. 
