4 PREFACE. 



aid derived from the writings of Messrs. Forbes, 

 Cook, Comstock, Lintner, Garman, Howard, Harvey, 

 Bruner, Webster, Saunders, Osborn, Gillette, Fletcher 

 and many others. 



The illustrations of this volume have also been 

 gleaned from various sources. Many of them were 

 printed from electrotypes obtained by duplicating a 

 series of cuts belonging to the Ohio Agricultural 

 Experiment Station, thanks to the permission of 

 Director C. E. Thorne ; and the rest have been gotten 

 from several sources. The original author to whom 

 each should be credited is indicated in the following 

 lists : 



After Riley :— Plate IV, and Figs. 1, 2, 4, 5, 9, 

 10, 13 (p. 40), 14, 16-20, 22, 23, 26, 36, 38, 39,41-43, 

 47-52, 53 (reduced), 54-67, 68 (reduced), 69, 70, 72, 

 87, 88, 90, 91, 92a, 98, 99-106, 113, 114, 116, 123, 

 125, 126, 127 (reduced), 130, 131, 133-135, 138, 140- 

 144 ; after Lugger, Fig. 6 ; after Harris, Figs. 15, 48 ; 

 after Harris and Saunders, Fig. 129 ; reduced from 

 Osborn, Figs. 137, 139 ; after Garman, Figs. 30, 33, 34, 

 37, 111 (reduced), 112 (reduced), 122 (reduced); after 

 after Bruner, Fig. 73 ; after Glover, Fig. 35 ; after Miss 

 ( hmerod, Fig. 136 ; after Harvey, Fig. 21 ; after Com- 

 stock, Figs. 28, 89, 109. Fig. 7 is from the Field 

 Force Pump Company, and Figs. 11, 27 and 28 have 



