44 



PSYCHE. 



March 1S91. 



through continuous progressive special- 

 ization to more and more differentiated 

 structure with correspondingly increased 

 functional powers, or larger or different 

 fields of work. At other times it may 

 lead us in a wave line, which follows a 

 devious course, rising part of the time 

 through progressive specialization, and 

 then falling for another period of time 

 through specialization by reduction. 

 If the animals under consideration be 

 parasites, they may continue on this 

 descending plane both in the growth of 

 the individual and the evolution of the 

 group. Nevertheless the resulting ad- 

 ult is not necessarily of "low grade" in 

 any scientific scheme of arrangement 

 founded upon the principles of evolu- 



tion. It is, however, farther removed 

 from the primitive type, and is extremely 

 specialized. The use of the aesthetic 

 terms "low" and "high" have come 

 from a period in the history of our sci- 

 ence when nature was made to assume 

 a rigidly progressive aspect, each divi- 

 sion of the animal kingdom representing 

 a finger-post pointing towards the so- 

 called perfect animal, man, each rising 

 higher and higher in the scale of per- 

 fection whose standard was the human 

 organization. Such artificial ideas re- 

 venge themselves, and words become 

 their ready instruments, first to express 

 what is false, and then to help in bind- 

 ing the mind with the conservative fet- 

 ters of habit. 



ON THE LIFE HISTORY OF DIABROTICA 12-PUNCTATA, OLIV. 



BY H. GARMAN, LEXINGTON, KY. 



{Co?icluded from p. JO.) 



THE INJURY TO CORN. 



The larva of this insect works much 

 like its congener, D. longicoi-nis, com- 

 monly destroying the roots, but often 

 also working on the underground part 

 of the stalk. The larva of D. longi- 

 cornis often makes a longitudinal bur- 

 row in a root leaving little outward trace 

 of its presence. The larval D. 12-func- 

 tata has not been observed to work in 

 this manner, the roots being mined and 

 channeled irregularly, often bored 



through from side to side, or even com- 

 pletely devoured where the worms are 

 abundant. Very few fields in Kentucky 

 are entirely free from injury, and many 

 are affected very injuriously, the damage 

 being perceptible to casual observation 

 in the retarded growth, and, as the sea- 

 sons advance, in the prostration of in- 

 fested corn by the winds. As a rule the 

 injury is greatest on land that retains 

 moisture longest. On high and well- 

 drained land it is not so prevalent. In 



