INVESTIGATION OF LIFK lilSTOHV. 39 



were oaten tluui inules, and another test wns })e<j:uii hy Mr. Collins to 

 determine whether (his preference was constant. 



Ten larvtE tliat hatched July 21 were isolated in jars and furnished 

 with 3 male and 3 female gipsy moth pupae, which number was increased 

 as the larvro rrrew and became more voracious. In this exi)eriment 

 each larva averaged to destroy 12 pupae, 17 per cent of wiiich were 

 males and 83 per cent females. In one case an adult female gipsy 

 moth was eaten by a Calosoma larva when pupa? of the gipsy moth 

 of both sexes were present in tlie jar. 



In order to check this experiment tliree localities w^ere visited by 

 1^'Ir. J. V. Schail'ner. jr., and Mr. II. L. MacKenzic for the purpose of 

 collecting the molted skins of Calosoma larv» and making counts of 

 the number of male and female gipsy moth pu})8e that had been 

 destroyed. 



Tlie first locality selected, in the Lynn woods, was badly infested 

 with caterpillars earlier in the season, and the larvae of sycophanta 

 had been foimd ])lentiful. All the trees had been banded with 

 tanglefoot, but owing to the fact that a considerable number of eaten 

 pupae, as indicated by the empty pupal shells, was found above the 

 sticky bands, it is probable that the bands had been applied rather 

 late in the season. Trees were also examined in tw^o other locahties 

 several miles from the Lynn w^oods, viz, at Mount Hood, Mass., near 

 the Melrose and Saugus line, and at Pine Banks Park, ]\Ialden, Mass. 

 In these two localities there wan no tanglefoot on the frees. A few 

 of the trees at Pine Banks Park were burlapped and most of them 

 had been s])rayed. The trees were climbed and a record kept of all 

 male and female gipsy moth pupae that liad been eaten by the 

 Calosoma larvae. The results for 20 trees examined showed that 

 24.5 per cent of the gipsy moth pupae eaten were males and that 

 75.5 per cent were females. These data correspond veiy closely with 

 those secured under laboratory conditions and indicate that the 

 preference of the larvae for female pupae is pronounced under field 

 conditions. The effect of the preference of the Calosoma larvae for 

 the female pupae of the gipsy moth is thus very apparent and indi- 

 cates that the benefit wdiicli is likely to accrue from this species may 

 be greater than was at first anticipated. 



EXPERIMENT IM FEEDIN(t EARTHWORMS TO LARViK OF CALOSOMA. 



In order to determine whether the larvae of Calosoma sycophanta 

 will feed on other than insect food, 5 newly hatched individuals w^ere 

 supphed with earthworms, as they had proved an acceptable diet for 

 several species of Carabus received from Europe. ^Ul the Calosoma 

 larvae died in the first stage, and none of the earthworms was eaten, 

 4 of the larvae lived 4 days, and 1 diet! at the end of 2 days. Tliis 



