NATURAL HISTORY OF AMIA CALVA LINNiEUS. 103 



22. The larvae hatch from the egg, in this locality, usually in from eight to ten 

 days, but this period depends on the temperature. 



23. The larvae are 12 millimetres long and ready to leave the nest in about 

 eighteen days after the eggs are laid or nine days after the eggs hatch. 



24. The 12-millimetre larvae are black, the yolk-sac is reduced, progressive 

 movements are well developed, the adhesive organ is no longer functional, and the 

 larvae are feeding. 



25. While in the nest the larvae develop an irregularly progressive swarm 

 movement. 



26. The larvae leave the nest in a swarm with the male and appear to follow 

 him by scent. 



27. The larvae are black until they are 30 to 40 millimetres long. 



28. The schools of black larvae are local in their habit, move slowly, are often 

 in open water, and form conspicuous black masses. 



29. A school of black larvae when separated from the male begins to circle and 

 continues this either as a whole or in fragments until reunited with the male. 



30. Black larvae do not show response to mechanical shock in the water, at 

 least not until their later stages. 



31. In strong light black larvae seek the shade. 



32. When between 30 and 40 millimetres long black larvae begin to show orange 

 and green colors, 



33. Schools of bright-colored larvae have not been observed to circle in search 

 of the male. 



34. Schools of bright-colored larvae respond to mechanical shock in the water 

 by scattering and hiding at the bottom; this reaction may also be present in the 

 later stages of the black larvae. 



35. Bright-colored larvae in strong light seek the shade more actively than 

 black larvae. 



36. The colors of bright-colored larvae are brighter in strong light, darker in 

 shade. 



37. The schools of bright-coloredjlarvae move more rapidly than those of black 

 larvae, are less conspicuous, and are rarely seen in open water. 



38. Larvae of all sizes above 12 millimetres come frequently to the surface for air. 



39. Schools of black larvae are more closely guarded by the male than those of 

 brightly colored larvae. 



40. Schools of larvae of greater length than 100 millimetres have not been 

 recorded. The schools probably disperse when the larvae are of about this size. [ 



