624 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



whitish; fourth, fifth, sixth segments nearly entirely blackish blue, 

 seventh whitish. Setae long, stiff, light brownish. Basal plate 

 nearly semicircular.'^ 



PART II. 



NOTES ON THE SEASONAL HISTORY AND BIOLOGY OF NORTH AMERICAN CLEBIDAE. 



The Cleridae are among the principal predators of wood and bark 

 boring beetles. They are predaceous in both larval and adult stages, 

 the adults attacking the adults of the destructive species while the 

 larvae feed upon the eggs and broods in the bark and wood. 



Under natural conditions they may be of but nominal importance 

 but can be turned to considerable account in control measures with 

 the additional help of man, who can overbalance the natural condi- 

 tions in favor of the predators by properly conducted control work. 



To benefit by their predaceous habits it becomes necessary to learn 

 as much as possible concerning their general habits and seasonal 

 history. 



With this Imowledge gained, control work can be conducted at 

 times best suited to the preservation of the predators or at least by 

 taking measures for their protection while destroying the host. This 

 would gi'eatly facilitate the control on barkbeetles as recommended 

 by Hopkins ^, which includes the percentage principle of control, 

 namelj' the disposal of 50 to 75 per cent of the tree-killing beetles. 



Whenever practicable the dissemination of Cleridae in quantities 

 in badly infested regions in addition to control measures would evi- 

 dently be of great value. Especially in the case of the genera 

 Thanasimus and Enoclerus among which are to be found the most 

 important economic species. 



The adults of most of the species of Cleridae are very active, and 

 when disturbed take flight readily or drop and crawl into the debris 

 upon the ground. 



Some of them are active at night, others in the daylight. Most of 

 them prefer bright sunny days when they may be observed running 

 over infested trees or on flowers. The nocturnal species may be ob- 

 served by the aid of a small searchlight upon infested trees. They are 

 attracted to artificial light and may be captured with trap lanterns. 

 The nocturnal species do not frequent flowers. 



Adult Clerids consume numbers of Scolytoidea and other small 

 insects. Sometimes they will attack insects much larger than them- 

 selves. In the usual method of attack the Clerid remains motionless 

 until a wandering Scolytoid or some other insect approaches close 



1 According to Bulletin 100, Bureau of Entomology, Department of Agriculture, 1912, 

 page 6S, a single specimen of the species Hydnocera pallipcnnis Say was reared April 6, 

 1907, but the larval skin was not saved. No larva determined as belonging to this species 

 is present in the special collections of the Bureau of Ehitomology nor in the general col- 

 lections of the United States National Museum in Washington, District of Columbia. 



2 Bulletin 83, pt. 1. Bur. Entom., U. S. Dept. Agri. 1909. 



