OBSERVATIONS ON LARVAE OF CORETHRA PUNCTIPENNIS. 285 



The 20 meter contour encloses an area of 664 hectares which 

 would give an annual crop of larvse amounting to substantially 

 797 metric tons, live weight, for this portion of the lake, or a dry 

 weight of about 67 metric tons. The live weight of all other 

 macroscopic inhabitants of this area was 92.3 metric tons and 

 their dry weight was about 19 metric tons. 



As previously indicated, the population of Corethra larvse in 

 the region between 8 meters and 20 meters averaged about one 

 third as large per unit area as that in the deeper water. In order 

 not to overestimate the annual production of the shallower water, 

 the area lying between the shoreline and a depth of 10 meters 

 may be omitted from the calculation since the number of larvae 

 found in this region is small ; in addition, also, the average 

 between the 10 meter and 20 meter contours, comprising an 

 area of 1,738 hectares, may be reckoned as one quarter instead of 

 one third as large as that of the deep water. On this basis the 

 live weight becomes 300 kilograms per hectare and the dry 

 weight 25 kilograms, thus making the annual crop of Corethra 

 larvae in this portion of the lake a little more than 521 metric 

 tons, live weight, or about 43 metric tons of dry material. These 

 results combined with those obtained for the deep water area give 

 a total annual production of 1,318 metric tons of living larvse 

 which would yield no metric tons of dry material. 



CHEMICAL RESULTS. 



The results of the chemical analysis of the larvae are shown in 

 Table V. and they are stated in percentages of the dry weight. 



TABLE V. 



RESULTS OF THE CHEMICAL ANALYSIS OF THE LARV.E OF CORETHRA PUNCTI- 

 PENNIS STATED IN PERCENTAGES OF THE DRY WEIGHT. 



The percentage of nitrogen is notably high, which means a cor- 

 respondingly large proportion of crude protein. The percentage 



