

THE GENUS CALOSOMA. 33 



HABITS OF LARVAE. 



Experiments were tried with larvae of this species in all stages to 

 secure data on their habits of finding food, using the apparatus show^ 

 in Plate III. 



June 24, 1912, Mr. Dudley began an experiment with two first- 

 stage larvae. They were placed several times upon the bark of the 

 tree, as they did not seem to venture there of their own volition. 

 When this was done they would either fall to the ground or advance 

 to the nearest loose scale of bark in their path and remain there until 

 disturbed. 



June 26 and 27, the two larvae molted to second stage. They 

 acted in a similar manner in this stage. They were usually found 

 buried in the earth in the morning instead of in the food cage at the 

 top of the tree. 



On July 2, one larva died in the second stage and the other molted. 

 The third-stage larva was put upon the bark of the tree several times 

 and would climb 6 to 12 inches around or down the tree before falling. 

 This larva became rather sluggish by July 12 and was removed from 

 the experiment. 



July 16, the junior writer liberated two large third-stage larvae in- 

 side the circle, and observed their movements at intervals for two 

 days, after which time they were becoming exhausted from lack of 

 food. One larva, when placed upon the trunk, ascended 12 inches 

 before falling, which was the best record for distance covered during 

 the period of the experiment. 



These experiments were repeated in 1913 with practically the same 

 result, except that in one case a first-stage larva after being placed 

 upon the tree was able to climb about 4 feet before falling. This is 

 the best record made by any larva of this species but hardly indicates 

 that the species commonly climbs to any marked extent. 



The movements of these larvae are very similar in all stages to 

 those of C. calidum and O.frigidum. It was necessary to remove the 

 larvae from the experiment at intervals in order for them to feed, in- 

 dicating that this species must secure food on or near the ground. 



COLONY AND CAGE EXPERIMENTS IN GREENHOUSE. 



During the early spring of 1910 it was necessary to secure lepidop- 

 terous larvae with which to feed specimens of Calosoma and Carabus 

 after their emergence from hibernation. After much inquiry, a sup- 

 ply was found in a range of greenhouses at Brighton, Mass. The 

 proprietor is a wholesale grower of roses, Asparagus sprengeri } and 

 Asparagus plumosus and his greatest insect pest on asparagus is a cut- 

 worm, Noctua clandestina Harr. There are several generations 

 annually and the proprietor and foreman report that the worms can 

 be found in various stages during most of the year. The proprietor 

 resorts to poisoned bran mash and hand picking to combat the pest. 

 He claims an annual loss of $2,500 from this insect which includes 

 $1,000 expended for hand picking at night and other methods, and 

 $1,500 damage as a result of the cutting oil* of the tender terminals of 

 the plants, which checks their growth. 



Cutworms collected by the laborers at night were used to (a\\ 

 Calosoma and Carabus. In return for this act of kindness in forward- 

 ing them daily to the laboratory during the early spring, an experi- 



54880°— Hull. 417—17 3 



