INSECTS AFFECTING GRAINS, GRASSES, ETC. 



79 



serious damage, and land which has been in sod and then 

 planted in corn, strawberries, or other crops of which they are 

 fond, is often so full of the grubs that the crops are ruined. In 

 1895 an Illinois field of 250 acres which had been in grass for 

 twenty years was so injured that the sod could be rolled up 

 like a carpet over the entire field. It is not surprising, therefore, 

 that Professor Forbes records finding as many as thirty-four grubs 

 to the hill of corn in another Illinois field which had previously 

 been in sod. Where sod is taken into greenhouses the grubs 



FIG. 57. Lachnosterna arcuata: a, beetle; 6, pupa; c, egg; d, newly-hatched 

 larva; e, mature larva; /, anal segment of same from below, a, 6, 

 e, enlarged one-fourth; c, d, f, more enlarged. (After Chittenden, 

 U. S. Dept. Agr.) 



often become serious pests. When the grub is two, or possibly 

 sometimes three years old, it forms a small oval cell from 3 to 

 10 inches below the surface and there changes to a soft, white pupa, 

 sometime in June or July. The pupal stage lasts slightly more 

 than three weeks, and in August or September the adult beetle 

 wriggles out of the pupal skin, but remains in the pupal cell 

 until the following spring, when it comes forth fully hardened. 

 Thus three full years are occupied by the life-cycle of each brood, 

 though grubs in all stages of development may be found in the 

 soil every year. 



The adult beetles feed at night upon the foliage of various 

 trees. They hide in the soil during the day, migrate to the trees 

 at dusk, and return to the fields just before daybreak. The 

 different species have favorite food plants, but all of our common 

 deciduous shade and forest trees are more or less eaten, poplar, 



