PAPERS OX BIOLOGY AND AGRICULTURE 109 



111 one aquarium where there were adult beetles the 

 egg mass was eaten and only the chorion or egg shell 

 remained. 



BREEDING HABITS 



The eggs are oblong cylindric, 0.2-1 mm. wide at the 

 end attached to the leaf, 0.48 mm. at the opposite end and 

 0.72 mm. long. The eggs are yellow when first laid, but 

 within a few hours change to ivory in color. The sur- 

 face of the chorion or egg shell is covered with small pits. 



Thirtj^-seven egg masses were counted, and the num- 

 ber of eggs in them varied from 6 to 15, confirming Need- 

 ham's work on this beetle in which he describes from 6 

 to 20 in the mass. The eggs are arranged in rows vary- 

 ing from one to five in each row. The following diagrams 

 will show several different arrangements. 



Four aquaria were set up with yellow waterlily leaves 

 in them, and adults that were found mating in the field 

 were brought in and one pair introduced into each aquar- 

 ium. The aquaria were set up July 15th. In one of them 

 egg masses consisting of 12 eggs were laid successively 

 on July 28th, Aug. 2nd, 4th, and 6th. Of the other aquaria 

 that contained the breeding beetles two pairs had not laid 

 any egg masses when the experiment was discontinued 

 Aug. 20th. In one aquarium the male died Aug. 3rd, 

 and another was put in Aug. 5th, but no egg masses were 

 laid. 



In one case the female was observed from the time 

 she began to deposit the eggs until she finished. It took 

 her one hour and twenty-eight minutes to deposit eleven 

 eggs. 



These are only a few observations and experiments 

 made on Galerucella nymphaeae, but the writer hopes to 

 do more on this problem in the near future. Very little 

 is known of the habits of this beetle. 



