379 



where they may be destroyed by carefully puUing up and burning 

 the plant, roots and all. 



S. caUosus, 01. (curlew bug) sometimes causes the destruction of 

 entire maize fields, most of the injury being caused by the feeding 

 of the grubs in the base of the stalk and tap-root. Eggs are laid 

 in maize, Cijperus escitlentus, C. strigosus, C. rotundus and probably 

 in a good many other plants. They are laid in the stalk either under 

 the soil or within an inch above the surface. During the egg-laying 

 season the adults rest under clods of earth. The egg-stage lasts 4 

 to 12 days, the larval stage from less than 39 days in midsummer 

 to more than 71 days in the autumn, development being quicker 

 with abundance of food. Pupation requires about 6 to 8 days. Hand 

 pulling is useless as a remedial measure as the tip of the root containing 

 the beetle often breaks off and remains in the ground. 



S. discolor, Mann., is not very destructive unless barley, oats or 

 wheat are planted very near marshes containing tule {Scirpus occiden- 

 talis). The damage is caused by the adults in the spring. It is not 

 known to breed in cultivated crops, and as only one season is required 

 for its development, clean cultivation for one year will eliminate it. 



S. pertinax, 01. (cat-tail billbug) is extensively destructive to 

 growing maize, of which it attacks the stalk from below the ground 

 surface, causing dwarfing of the plant. The adults are active from 

 April to August and hide in the soil. Eggs are laid in June about 

 cat-tail and other reeds. Hibernation probably takes place in the 

 pupal stage. 



S. destructor, Chitt., the adults of which are known to Hve nearly 

 a year, one female laying at least 30 eggs, is frequently found in 

 the same field as S. ccdlosus, its food-plants being similar, 



S. venatus. Say, is destructive to timothy and maize. The habits 

 of the grub are little known, but it develops in wheat and timothy. 

 The adult injures wheat and maize, its activity lasting from April 

 to August or later. 



S. phoeniciensis, Chitt., attacks the tender stools of wheat and 

 barley in the spring, the injury not being noticed until it is too late 

 to restore the crop, but prompt irrigation may save a part by stimu- 

 lating growth. The damage continues until June and may even 

 occur in the warm winter months, Oviposition takes place in the 

 punctured tips of plants. The injury caused by this pest in wheat 

 or barley may amount to 100 per cent. The life-cycle from 

 egg to adult requires about 2 months ; the eggs laid in March and 

 April hatch in about 8 to 12 days ; those laid in May in 6 to 8 days. 

 Pupation takes place in earthern cells in the soil. 



S. minimus, Hart (httle billbug) works beneath the surface, the 

 damage done being consequently difficult to ascertain. Its food- 

 plants include timothy, quick grass and wild rye {Elymus virginicus). 

 The egg -period is less than 8 days, the larval stage 27-33 days and 

 the pupal 7 or more days. The entire development requires from 

 60 to 70 days. 



The natural enemies of these weevils include fungus parasites, 

 toads, insectivorous birds, etc. A Hymenopterous parasite, Zavipio 

 belfragei, Cress., has been bred from S. ccdlosus. 



Clean cultivation, autumn ploughing, rotation of crops and improved 

 drainage are suggested as the best remedial measures. In the case 



(C588) b2 



