224 IOWA ACADEMY OF SCIENCES. 



NOTES ON COCCID^ OCCURRING IN IOWA. 



HERBERT OSBORN. 



Aside from the interest attaching to this family of the Hom- 

 optera as a remarkably specialized group of insects, the fact 

 that it includes some of the most destructive insects affecting 

 woody plants, and that one member of the family, the San Jose 

 scale, is at present spreading rapidly throughout the eastern 

 United States, and a most serious menace to the fruit interests 

 of Iowa, is sufficient reason for giving it a special notice at this 

 time. It seems also unnecessary to apologize for including in 

 this article some matter for the use of teachers, students, and 

 others who may be called upon to examine scale insects in con- 

 nection with the popular interest that is bound to appear with 

 4ihe further extension of the San Jose scale. 



The Coccidas in general are scale -like insects that with few 

 exceptions become permanently fixed to the bark upon which 

 they occur. The females once fixed never leave the point of 

 attachment unless it be to move from leaf to twig for winter 

 security, but the males undergo a very marked transformation 

 and appear as delicate bodied creatures with one pair of wings. 



In a few cases as with the mealy bugs, attachment is not 

 permanent and no scale is formed, while of the scaled forms 

 there are two distinct types, the shield or armored scales 

 (Diaspinas), having a separated waxy scale, and the unarmored 

 scales (Lecaninse), having the waxy secretion not separated 

 from the body. 



Our state fauna includes representatives of all the sub- 

 families, and in an enumeration of the species we can point out 

 the characteristics and give such details of generic structure 

 as will be of service to those specially interested. 



A number of the records given here are based upon specimens 

 collected by Mr. Wilmon Newell. 



