260 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 34 



Most of the grass-feeding forms still retain their original food 

 plants and habitat while reaching out to conquer new worlds. The 

 grass-feeding cutworms and wireworms often occur on crops in out- 

 break proportions, particularly on wheat, corn, and alfalfa. Small 

 armyworms are said to overwinter in grass plots. The fall army- 

 worm often appears in numbers in bentgrass lawns or plots before 

 it does in wheat or alfalfa. The army cutworm, the greasy and well- 

 marked cutworms, when scarce, can often be collected to best ad- 

 vantage in grass lands, under stones, boards, or trash. Likewise, 

 certain species of wireworms occur in similar locations, especially 

 in the early spring. It is but a short step from the wild grasses 

 to the cultivated ones, such as corn, wheat, sorghums, etc. White 

 grubs are worst in grassy fields or gardens. It is but a short step 

 from feeding on the roots of lawn and pasture grasses to strawberries, 

 potatoes, corn, and many other crops. 



The wheat stem maggot {Mero^m/yza mnericana Fitch.) has shifted 

 from wild grasses to wheat and has found the change advantageous. 

 False wireworm larvae formerly fed on weed seeds and decaying veg- 

 etable matter on or under the surface of the soil in the Great Plains 

 region. It was a logical move to feeding on the kernels of fall-sown 

 wheat in the drier portion of the Great Plains States when germina- 

 tion was delayed. 



The mole crickets, normally satisfied with the roots of grasses, 

 damage potatoes in the Gulf States, while the Puerto Rican mole 

 crickets, lifting the soil around young celery plants in Florida, have 

 become major enemies to the celery growers. 



The tile-horned Prionus (Pf'ionus imbricornis Linn.), a native in- 

 sect feeding among the roots of big bluestem grass, has lately been 

 found to be a serious apple-tree pest in Arkansas. 



The harlequin cabbage bugs, striped cucumber beetles, melon 

 aphids, and tarnished plant bugs all find food plants more diverse 

 and favorable as a result of modern agriculture, and are probably 

 more plentiful as a result of it. 



Termites probably were natural feeders on sod, shrub, and forest 

 remains before civilization provided houses with the attractive oak 

 and hard pine floors. In their former role, termites were nature's 

 aids in the return of humus to the soil. Now they are aids chiefly 

 to carpenters and lumber dealers by making rebuilding and re- 

 pairing necessary. 



The shift from wild food plants to cultivated ones is most marked 

 among fruit insects.® From wild plum came the plum curculio and 

 the peach-tree borer; from hawthorne the apple maggot, the lesser 



* Herrick, Glenn W. Manual of injurious insects, p. 18. Henry Holt, 1925. 



