CORRESPONDENCE, 



HARRIS TO LECONTE. 



CAMBRIDGE, Jan. 23, 1849. 



Blethisa quadricollis, when placed by the side of my species, 

 proved to be obviously distinct from the latter, for which, there- 

 fore, my name of B. americana remains good. The distinction 

 was not only plainly perceptible to myself, but was immediately 

 recognized by Professors Agassiz and Pierce, to whom the in- 

 sects were shown. I know not what standard of measurement 

 Prof. Halcleman used, in making his B. quadricollis to be seven 

 and one half lines long and three wide. I use the English 

 inch, divided into tenths or hundredths, and in measuring the 

 length exclude the mandibles. My female B. americana meas- 

 ures six tenths of an inch in length, and not more than one 

 hundredth of an inch less than three tenths of an inch in its 

 greatest width. B. quadricollis I make to be also six tenths 

 long, but only two and one half tenths broad. There is not 

 the slightest vestige of a tooth on the under side of the anterior 

 femora in quadricollis; neither is there any in the female 

 of my americana. I may add, what you probably have 

 observed, that quadricollis is a female, and that it has the 

 anterior femora incrassated, as in the female americana. The 

 quadricollis, compared with the female americana, wants the 



