88 PZlGHTEENTH RePORT StATE ENTOMOLOGIST OF MINNESOTA — 1920 



card the equivalent in millimeters of all the micrometer readings from 

 1 to 100. Thus by a glance at the table one may read ofT in millimeters 

 any micrometer measurement. Such a table is easily worked out by 

 taking micrometer measurements on a standard millimeter rule which 

 reads at least in tenths of a millimeter. Repeated measurements should 

 be taken to ascertain the exact number of millimeters represented in 

 say forty or fifty of the micrometer divisions, then by dividing one can 

 find the length of a single micrometer division in thousandths of a 

 millimeter. By a series of nuiltiplications the taljle may be prepared 

 and thus save future computations of this nature. 



W .UJ SjJ 



uy 



Fig. 2. Claws and aiolia of representative species of Deraeocoris and Deraeocapsus. 

 A, Deraeocoris atrhtentriH ; B, D. pinicola ; C, D. nigritiilus: D, D. sai/i : E, D. nebulosus ; 

 F, p. rubir; G, D. olivaceus ; H, DeraeocaiJsus ingens. 



KEY TO THE GROUPS OF NORTH AMERICAN SPECIES OF 

 DERAEOCORIS 



1. Claws deeply cleft near base (fig. 2, D-G.) 



Claws not cleft or with only a slight indication (fig. 2, A-C) 



2. Scutellnm punctate ........ 



Scutellum inipiuictate ........ 



