KECORD OF TWO FIELD COLONIES OF BEETLES. 77 



late summer scouting, in which work it was necessary to employ 

 several assistants in order to cover the extensive territory which was 

 examined, indicated that the beetles had spread over a much larger 

 area than had been anticipated, and this is shown on the above- 

 mentioned map (PL IX). In order to give an idea of the reproduc- 

 tion and dispersion under actual field conditions, a somewhat detailed 

 account will be given of two colonies, namely, Saugus and Wellesley, 

 Mass. 



RECORD OF TWO FIELD COLONIES OF CALOSOMA BEETLES. 



In July, 1907, Mr. Mosher liberated 331 beetles as soon as they were 

 received from Europe in badly infested woodland near the old para- 

 site laboratory at North Saugus, Mass. Larvae of sycophanta were 

 found later in the month and during the following year they were 

 quite abundant. As there were plenty of gipsy moth caterpillars and 

 pupae for them to feed upon, it seemed desirable to determine the 

 extent of spread and the amount of increase of the Calosoma beetles 

 during the summer of 1908. In order to do this the woodland was 

 examined thoroughly in August, and counts made of all the molted 

 skins found. All the trees were climbed, and the rough bark, which 

 was likely to harbor molted skins, was inspected, as were the masses 

 of gipsy moth pupae and the burlaps. Ninety-three first-stage and 

 294 second-stage molted skins were found in an area of about six 

 acres, which seemed to represent the limit of spread of the species. 

 That this was not the limit of spread, however, was definitely shown 

 the next summer when larvae and molted skins were found at inter- 

 vals for more than half a mile in every direction. 



In the fall of 1910 the colony was examined in the same manner 

 as in 1908, and in the territory inspected the latter year 733 first- 

 stage and 848 second-stage molted skins were found. This indi- 

 cates that there had been an increase of the beetles in the center 

 of the colony as well as a general dispersion of the species. A small 

 block of trees adjoining this area was examined and molted skins 

 were found in about the same relative numbers. A record of the 

 dispersion from this colony could not be secured, because in 1909 

 it had merged with other colonies planted a mile or more distant. 



'In order to check up this data a careful scout was made, in the 

 fall of 1908, of a colony at Wellesley Farms, Wellesley, Mass. The 

 beetles that were placed in this colony, 105 males and 1 10 females, 

 were received from Europe late in June, 1908, and were liberated 

 July 1 of that year. The timber growth, which was chiefly oak, 

 with trees of from 4 to 10 inches in diameter, had been burlapped, 

 and two men were employed to destroy the gipsy moth caterpillars, 

 as the infestation was bad. The beetles were liberated in two spots 

 about 300 yards apart. The scouting in this colony consisted in 



