The Bulletin. 



19 



eggs are usually laid in two rows, each containing six eggs, but one 

 female will lay several such clusters of eggs. They are usually de- 

 posited on the under side of the leaf, are pearl gray in color, with black 

 markings, barrol-like in shape and quite hard, so that in pinching hard 

 enoui>;h to crush them the leaf is bruised. It seems that nature has 



Fig. 8.— Eggs of Harlequin Cabbage Bug. Enlarged. (Photo by Z. P. Metcalf.) 



pretty definitely fixed twelve as the normal number of eggs to be laid 

 at a time, as Prof. Smith found that bugs which laid either over or 

 under this number would even up at the next laying, or if they laid more 

 or less than twelve for several times in succession they would die. 



Mr. Smith tested the egg-laying powers of fourteen different females 

 which appeared early in spring. Of these one short-lived bug died on 

 April S6, after laying three batches of twelve eggs each. But the prize 

 breeder in this series of tests laid fifteen separate batches of eggs, the 

 first on April 7th, and the last on June 9th, having laid in all a 

 total of 179 eggs. She died the second day after laying the last lot of 

 eggs. Prof. Smith concludes that the average number for these early 

 spring females is about 100 eggs.* 



Prof. Smith also attempted to ascertain whether the bugs of the 

 second generation were equally prolific, but found that (at least in the 

 case of the specimens he confined) the mortality was so high that com- 

 pletely satisfactory results could not be obtained. Out of fourteen bugs 

 at the start on August 10, seven died by August 27, after laying from 

 one to three batches of eggs. Three more had died by September 7, hav- 

 ing laid only thirty-six eggs each, and another died only a few days 

 later, having laid four batches with a total of forty-six eggs. Of the 

 three that remain-ed one laid six batches with seventy-tw^o eggs, another 

 six batches with a total of seventy-one eggs, and the third laid seven 

 batches with a total of eighty-four eggs. Prof. Smith concludes that 

 while the lesser number of eggs which these second brood bugs laid 

 may have been partly unnatural, yet that they are not so prolific as 

 the ones that pass the winter. He believes that the females of the 



*To be exact 99 1-9 eggs. 



