GROWTH AND FEEDING OF HONEYBEE LARVAE. 



On July 12, 20 eggs from the same colony, proving on microscopic 

 examination to be only a few hours old, weighed 2.65 milligrams, 

 average 0.132 milligram. On July 13, 20 eggs from the same frame 

 weighed 2 milligrams, average 0.1 milligram. On July 27, 1916, 

 20 eggs taken at random, and found on examination to be in differ- 

 ent stages of development, weighed 2.3 milligrams, average 0.115 

 milligram. Since newly hatched larvae weigh about 0.1 milligram, 

 this may be taken as the average weight of eggs about to hatch, 

 earlier stages being somewhat heavier. 



RATE OF GROWTH OF LARVAE. 



Data regarding the rate of growth were secured in 1915 and 1916 

 for seven lots, five of these representing weighings made at 24-hour 

 intervals (Table 1). The histories of these lots were as follows: 



Lot 1 (July 14, 1915). — Ten larvae of fairly uniform size from a 

 single frame, surrounded by larval jelly which covered one-third to 

 one-half of the bottom of their re- 

 spective cells, were found to weigh 

 exactly 1 milligram, and may 

 therefore be considered newly 

 hatched. About 50 cells contain- 

 ing such larvse, all on the same 

 side of the frame, were marked. 

 Weighings were thereafter made 

 at 24-hour intervals, 10 larvae taken 

 at random being included in the 

 first two weighings and 5 in each 

 of the three succeeding. The 

 and other lots are 

 1. On the third 

 evident a notice- 

 in the size of the 

 larvae, one being appreciably larger 

 than the others. This individual 

 weighed 25.3 milligrams, the aver- 

 age weight of the other four being 

 only 12.75 milligrams. When seen curled up in their cells, larvae of 

 this age occupy from 60 to 75 per cent of the diameter of the bottom of 

 the cells. On' the fourth day the weight of the smallest of the five 

 larva? was 50 milligrams; that of the largest, 89.5 milligrams. The 

 larvae at this time filled the bottom of the cells snugly and there was 

 no trace of larval jelly. On the fifth day the two largest in the lot 

 of five weighed together 328.15 milligrams, an average of 164.07 milli- 

 grams. The remaining three together weighed 450 milligrams, an 

 average of 150 milligrams. Two of the five were sealed, two not 

 sealed, and one partly sealed. 



Lot 2 (June 28, 1916).— A number of cells on a single frame con- 

 taining larvae chosen as newly hatched were marked. On June 29, 

 10 larvae weighed 10.2 milligrams, or 1 milligram each, which is 

 more than twice the weight of the larvae of the same assumed age 

 in Lot 1. This of course means either that the larvae originally se- 

 lected were too old or that the rate of growth during the first day 

 was more rapid in this case. This difference continues up to the 



weights of this 

 given in Table 



day 

 able 



in 

 there was 

 difference 



Fig. 1. — Outline sketch of newly hatched 

 honeybee larva, as seen through the 

 microscope in conjunction* with an eye- 

 piece micrometer composed of a fine 

 wire ring, having an inside diameter 

 of 1.1 millimeters. 



