153 



Additions to the List of Gall-Producing Insecta Common to 



Indiana. 



By Mel T. Cook. 



One year ago the writer presented a list of gall-producing insects, 

 with a list of host plants, for the State of Indiana. This list is uo 

 doubt very incomplete, since the writer has collected specimens in Illi- 

 nois and Ohio which have not been reported from Indiana. Further- 

 more, this collection of galls which I have received from other parts 

 of the United States and Canada lead me to believe that galls have 

 a very wide distribution; it is probalile that the galls are distributed 

 over as wide an area as the host species and, in some cases, are as 

 widelj- distributed as the host genera. However, the insects may in 

 some ca.ses be restricted to smaller areas, due to other environments. 

 Our Icnowledge of American galls is at present so limited that it is 

 impossible to draw any dehnite conclusion on this subject. 



"Witliin the yast year I have collected a large number of galls in 

 Illinois, Indiana, and Ohio, but, of course, many of these duplicate those 

 reported in the list of one year ago. I have also received collections 

 from various parts of the United States and Canada, and wish espe- 

 cially to thank Mr. F. L. Sims, of I>aporte. Indiana. Mr. C. C. Deam, 

 of Bluffton, Indiana, and Prof. W. A. Kellerman, of Columbus, Ohio, 

 for interesting collections of Indiana galls. 



The additional list which I now present gives an increase of two 

 genera and eleven species of insecta. 

 Hoxiptcra : 



41. Pemphigus populis-caulis, Riley, on Populus deltoides Marsh. 



42. Pempliigus populis-transversus, Riley, on Populus deltoide.s 



Marsh. 

 Diptera : 



43. Sciara ocellaris, O. S., on Acer saccharium L. 



44. Cecidomyia holotricha, O. S., on Hicoria alba L. (Britton.) 



45. Cecidomyia tubicola, O. S., on Hicoria alba L. (Britton.) 

 f{y»ic)wpter(i : 



