40 CALOSOMA SYCOPHAKTA. 



experiment served to indicate the approximate length of time which 

 young larvae can survive without food, although a more detailed 

 experiment of this sort follows. 



Starvation Experiment Applied to Larv.e of Calosoma Sycophanta. 



Early in the spring of 1908 a series of experiments was carried on, 

 using 5 beetle larvae in each stage in order to determine how long 

 they would remain alive and active without food. 



August 3, 1908 ; 5 newly hatched beetle larvae were placed in jars 

 of earth without food; 2 larvae died in 3 days, 2 in 4 days, and 1 in 

 5 days. 



August 3, 1908, 5 larvae that had just passed the first molt were 

 placed in jars of earth without food; 1 larva died in 6 days, 3 in 7 

 days, and 1 in 9 days. 



August 6, 1908, 5 larvae that had just passed the second molt were 

 placed in jars of earth without food; 2 larvae died in 8 days, 1 in 10 

 days, and 1 in 16 days. 



The remaining larva, after having been confined, without food, in 

 a jar for 9 days, was offered fall webworms. It consumed 5 larvae in 

 3 days, but at the end of that time died. 



Tins experiment shows that the older Calosoma larvae are able to 

 survive without food for a longer period than the } T ounger ones. In 

 nature they will probably live longer than the time indicated, as 

 they would be able to obtain considerable moisture wdiich would help 

 to prolong life. 



In order to determine how late in the summer it is possible to plant 

 larval colonies of Calosoma sycophanta successfully, two experiments 

 were tried in 1908. 



On August 7, 1908, 100 Calosoma larvae that had passed the second 

 molt were liberated in woodland at Waltham, Mass. No gipsy moth 

 caterpillars were present at the time, but a few newly hatched 

 brown-tail moth larvae were feeding on the trees. No native cater- 

 pillars were observed at the time the Calosoma planting was made. 



In the spring of 1909 the trees in this colony were burlapped and 

 examinations were made at intervals throughout the summer. In 

 September a molted larval skin of the Calosoma was discovered on 

 one of the trees, and the following summer (1910) beetles, larvae, and 

 molted skins were found, showing that some of the Calosoma larvae 

 in the original planting had developed and that the strength of the 

 introduced colony was increasing. 



In order to test the matter under still less satisfactory food condi- 

 tions, a colony of 100 third-stage Calosoma larvae was liberated in 

 the oak woodland at Tewksbury, Mass., August 12, 1908. The larvae 

 were placed at the base of each of six oak trees, the foliage of which 

 was being eaten by small brown-tail moth caterpillars. Tins colony 



