INVESTIGATION OF LIFE HISTORY. 65 



Spocinieiis coiiiiiiod in cn^Jics or jars liavc Ixmmi ()l)S('rvo(l to vibrate 

 ihe wings rapidly. Tliis is usually done soon after the IxH'tlos emerge 

 from liibernation or toward evening. 



A large cage of the native species, C. scrutator, was kept under 

 observation one evening in June, and after twilight tlie beetles flew 

 about the cage freely. This habit is well developed in this species, 

 as the beetles are frefpiently taken at electric lights at night, in 

 localities wliere they are abundant. 



Apparently si/cophanta must have the ability to lly, or the disper- 

 sion of the species in the field could not have been so rapid as is 

 sJiown later in this report.' 



Attkaction of the AfJULTs TO Light. 



As has been already noted, C. scrutator is frequently captured at 

 electric lights. This does not often happen in New England, as the 

 species is comparatively rare, but at Washington, D. C, and farther 

 south, specimens can be commonly secured at arc lights during May 

 and June. 



Calosoma frigidvrn has this habit to some extent, as 2 males were 

 captured at light traps at Reading, Mass., June 22, 1910. 



Several observations have been made at electric arc lights located 

 near colonies of C. sycophanta, but thus far no evidence has been 

 secured which indicates that the beetles are subject to this attraction. 

 Lights near a strong field colony at Oak Island, Revere, Mass., have 

 been under observation when tune permitted. No reports have been 

 received from any of the field men that the beetles have been found 

 at lights. 



Drowning Experiments with Beetles. 



March 17, 1910, cages containing frozen earth were dug up, and 2 

 male beetles were removed from their cavities and put in a jar of 

 water. At 11 a. m. the jar was placed in the laboratory ice chest 

 and kept at a temperature of 39 degrees F. Some pieces of cloth 

 and two small blocks of wood were put in the jar with the intention 

 of keeping the beetles submergetl, but at 5.58 p. m., when an exami- 

 nation was made, both beetles were found swimming about in the 

 water. They were again sid)merged by placing a f[uantity of blot- 

 ting paper inside of the jar, but on the following morning they had 

 succeeded in making their way to the surface. A wooden float was 

 then constructed which was placed in the jar in such a manner as to 

 keep the insects under water. They were kept in this position 4 

 days, although every 12 hours they were taken out and examined 



> During the last few days of May and the first part of June, 1911. both sexes of xijcophanta were 

 observed to fly freely in the field. This was shortly after emergenoc frotii liiheniiuion and the beetles 

 proliMljly do not fly freely later in the season. 



100834°— Bul. 101—11 5 



