96 



NATURAL HISTORY OF AMIA CALVA LINNAEUS. 



each circle to the original spot (not a nest). The circles became gradually larger, 

 and in twenty minutes had expanded from 30 centimetres in diameter to about 2 

 metres. Meantime the return to the original spot became less frequent and less 

 definite. The school also broke in two during this manoeuvre and a good many 

 scattering larvae were left as stragglers. At the end of twenty minutes a chance 

 movement on my part frightened the male, which had returned to within 20 centi- 

 metres of my heel. I then left the school, but within twenty minutes found it 

 again reunited with the male, which was seen to drive away an encroaching sunfish." 

 These larva were 16 millimetres long. On another occasion, when I reached the 



Fig. A. — Plan showing the movements of a school of 20-mm. larvse during fifteen minutes while the male was absent. 

 A, point of departure of the school; B, point where either the school or the male had probably lain for some time 

 previously; C, point to which the male returned and where the school stopped; dotted areas, grass-covered 

 hummocks; lined areas, grass tufts. Scale -fa. 



swarm the male, which had previously been frightened away, returned to his orig- 

 inal position and then retreated to a point some 3 metres from this position and 

 there remained at rest. "The school was now circling widely in three main bodies 

 and in several smaller groups of six or eight individuals. After much circling one 

 of these sub-schools came upon the male and immediately stopped. Later a second 

 sub-school also joined the male, coming to him from the side and in front. As the 

 larvse approached he turned toward them and moved a few inches in their direction. 

 Several of the smaller groups then joined the male from behind, one after another. 



