Dec, 'o6] 



ENTOMOLOGICAL NEWS. 



369 



number of eggs laid in each nest is rarely if ever less than 

 500, and must often exceed 2000, though as I have not at- 

 tempted to count the number in the larger nests this is only 

 an estimate." * * * "Dr. S. S. Rathvon states, in his paper 

 in Pennsylvania Farm Journal, 1854, that he counted in one 

 of these nests 564 living insects and over 300 eggs not hatched. ' ' 

 Mr. S. A. Johnson, in Bulletin 116, of The Colorado Agri. 

 Exp. Sta., says, "The number as given by the older ento- 

 mologists is from one to two thousand. These figures are 

 probably somewhat too large and more recent writers have 

 reduced the estimate. Cotton mentions from three hundred 

 to one thousand and Sanders says that the number may reach 

 fifteen hundred." 



The egg masses counted were from individual females and 

 no choice was made as to the size. They were taken at 

 random and are examples of the average-sized nests. All 

 were collected June 19, 1906, at Lincoln Park, Chicago, 111. 



The following table shows the number of eggs per nest : 



Average per nest 3410.2. 



Culex pipiens Linn. 



The following table shows the number of eggs in single egg 

 masses of the common house mosquito, Culex pipie?is y the 

 average of the ten masses being 178.4 eggs per mass. 



Average per mass 178.4. 



