ADJUSTMENT OF ORGANISMS TO ENVIRONMENT 421 



Separate out the species in suitable receptacles for keep- 

 ing alive. Remember that all are carnivorous, and that the 

 larger ones if pressed by hunger may eat the smaller; 

 remember also that all can climb and fly, and cover vessels 

 accordingly. 



The record of this study may consist in a diagram on the 

 plan of the left hand side of fig. 224 on page 385, with the 

 names and places of all diving beetles collected indicated 

 therein. 



Study 58. The adaptive structures of diving beetles. 



Materials needed: Preserved specimens of the same 

 species used in the preceding study. 



Study these species one by one, and record the more 

 obvious characters called for in a table prepared with the 

 following column headings : 



Name. 



Sculpture (development of furrows or structural ornamen- 

 tation, especially of the back). 



Vesture (development of hair on the body, especially of 

 the back). 



Scutellum (visible or hidden). 

 j Femur: | 



Relative length < Tibia : > expressed in ratio I :x :y 

 (Tarsus, j 



. . f On what legs developed 



Specialized swimming fnnges "j Relativeexcellence 



( Number (one or two) 

 Claws < Equality (equal or unequal) 



( Mobility (fixed or movable) 



Special braces (such as the overlapping lobe of the femur, 

 which serves to steady the action of the tibia, and to keep 

 it moving in one plane : developed where on legs) . 



