CRANBERRY STATION. 161 



On July S, 1919, the vines inside the boilers were removed and the sand 

 do^^'n to the peat, about 7 inches deep, was taken out and carefully sifted. 

 Amphicoma grubs were found as follows : — 



Table 10. — Root Gnthsi found in Boilers at Station Bog July S, 1919. 



The grubs from the first three boilers were evidently what were left 

 of those put in in 1917, larger gro%\Ti. Those from boiler 4 probably were 

 a new brood produced by beetles of the grubs put in in 1917. Grubs of 

 the smaller sizes probably were a j^ear or more old when put in the boilers 

 in 1917, and the size of those taken from boilers 1, 2 and 3 in 1919 sug- 

 gests that they required another year to mature. Evidently, therefore, 

 the grub stage lasts three or four years. 



On July 1, 1920, the grubs were found in numbers among the fine cran- 

 berry roots of bogs, -nithin 3 or 4 inches of the surface. On July 28, in the 

 same places, they hardly could be found among the roots, but were abun- 

 dant 6 to 10 inches below the surface, many being in the peat under the 

 sand. One was 4 inches deep in the peat. On December 3, in the same 

 locations, they were 3 to b\ inches below the surface, the lowest being 

 near the water table. It seems from this that the insect works deeper into 

 the soil as a bog dries out in summer and comes up again with a rise of the 

 water. 



The Army Worm {Cirphis unipuncta Haw.). 



In previous reports,' the fall armj' worm {Laphygma frugiperda S. & A.) 

 and the greasy cutworm (Agrotis ypsilon Rott.) were mentioned as harm- 

 ing bogs after removal of the winter fiowage in July. In 1919 a destructive 

 visitation of the army worm under like circumstances on a bog at Mays 

 Landing, N. J., was reported, worms of the infestation one-third to one- 

 half grown being brought to the writer on August S. Moths reared from 

 these worms emerged September 9 and 10. The winter water had been 

 let off from this bog about July 5. 



On July 20, 1920, army worms, many nearly mature, were found damag- 

 ing a bog at Assonet, bared of its winter flowage June 16, and on July 24 

 they were found abundant on a bog in Carver, bared of its flowage July 

 2, the largest being one-fifth to one-quarter grown. It is noteworthy, in 

 connection with these infestations, that this pest was prevalent in most 

 of the Mississippi Basin in both 1919 and 1920. The former year it was 



» Mass. Agr. Expt. Sta., Bui. No. 180. 1917, p. 232; Bui. No. 192, 1919, p. 133. 



