RESULTS OF CROSS! N(i TWO HEMIPTEROUS SPECIES. 197 



Hoping that such a marked difference in the chromosomes 

 might be a constant feature, we anticipated being able to obtain 

 some interesting comparative results by crossing the two species. 

 We were disappointed, however, to find that in all the individuals 

 we studied the inequality in the size of the idiochromosomes of 

 E. serrus is quite as marked as in E. variolarius, and that the 

 chromosomes of these two species were therefore of no special 

 value for this comparative study. 



This seems to be another case pointing to inconstancy in the 

 morphology of the chromosomes as the individuals which 

 \Yilson studied showed a marked feature which was absent in the 

 individuals studied by us. All such examples of inconstancy in 

 vital processes throw additional light on the fact that investi- 

 gators of the same material so frequently hold diametrically 

 opposed views as to the fundamental significance of such ex- 

 pressions of vital activities, and that facts in support of these 

 opposing view r s can be demonstrated in the same material. 



This is almost amusingly illustrated by two recent papers on 

 the cytology of certain Hemiptera, Gross ('12) and McClung 

 and Pinney ('12). Gross differs from Wilson as to the facts on 

 almost every point in which their hypothetical views clash. 

 Of the cytological evidence for Wilson's theories, he says, "Ge- 

 leitet von einigen Gesichtspunkten, die ich bei der Untersuchung 

 von Syromastes und Pyrrhocoris gewonnen hatte, habe ich aus 

 dem Studium cler Literatur den Eindruck erhalten, das die 

 scheinbar so sichere cytologische Basis von Wilson's Theorie 

 hochst unzuverlassig ist. Ja, man kann mit gutem Grunde 

 sagen, sie existiert eigentlich gar nicht." 



He denounces Wilson's work on Syromastes as follows: 



"Im einzelnen enthalt Wilson's recht kursorische Darstellung 

 zahlreiche, leicht nachzuweisende Liicken, Ungenauigkeiten und 

 Irrtumer." 



McClung ('12) condemns our work on Anasa tristis with quite 

 as firm a hand, attributing to our methods of technique our 

 failure to demonstrate the facts which he considers of most 

 value. With the finality of a judge he hands down his decision: 

 "It is my judgment that this method ' used alone' is entirely 

 inadequate for accurate results, and in this particular case is 



