1914.] NATURAL SCIENCES OF PHILADELPHIA. 329 



tested. To decide definitely about the relative sensitiveness to 

 odors of insects, it is, therefore, necessary to consider (1) the degree 

 of agility or sluggishness in responding when stimulated; (2) the 

 degree of development of the entire nervous system, including the 

 'olfactory apparatus; and (3) the physiological state or condition 

 in which the insects are in when being tested. 



Table II. — The Number of Olfactory Pores and the Relative Sensitive- 

 ness of Various Species of Hymenoptera. 



The letters "F," "M," "H," and ''G" stand for front, middle, 

 hind, and grand, in the order named. The "Total" means all the 

 pores found on all six legs, and the "G. total" means all the pores 

 found on all six legs and all four wings combined. "1 R. Sen." 

 means the relative sensitiveness to odors of an insect based on the 

 morphology of the olfactory pores found on the legs; "2 R. Sen." 

 means the same based on the grand total number of pores. 



