264 WEST VIRGINIA EXPERIMENT STATION 



on the living adult, and when the egg hatches, the maggot 

 enters the abdomen of the beetle, where it absorbs its nutriment 

 from the liquids of its host until it is full grown, when it emer- 

 ges from its victim and changes to the pupa and adult prob- 

 ably in the ground. Remarkable as it may seem, the beetle 

 remains alive and active until after the parasite larva leaves it, 

 although the full grown maggot almost fills the abdominal 

 cavity of its host. Just how common these enemies of the 

 Clerid are, and to what extent they reduce its numbers, it is 

 difficult to judge, but since I have only bred one example of the 

 fly, and only one or two of the Braconid, and have bred probably 

 one hundred examples of what is, evidently, a parasite of the 

 Bracon larvae from two of the Clerid larvae, it woald appear 

 that these parasitic enemies of the Clerid cannot be very nu- 

 merous. 



This beneficial insect has another class of enemies in insecti- 

 verous birds, by which its numbers are greatly reduced, since 

 they are exposed to attack while running about on the bark 

 and are easily procured by woodpeckers from their pupa cases 

 in the outer bark. 



During the early investigations in the spruce and pine forests 

 in 1892, this insect and other enemies of the bark beetle ap- 

 peared to be rare, but in the fall of 1892 and the spring of 1893, 

 they were abundant. 



Two or three other species of Clerids, (see appendix,) have 

 been found with the spruce bark beetles, but since their gen- 

 eral appearance and habits are similar to the one just men- 

 tioned, it is not necessary to discuss them further. 



STAPHYLINID OR ROVE BEETLES AND THEIR LARVAE. 



Numerous representatives of the rove beetle class or family 

 of insects were found associated with the spruce bark beetles 

 and their young, and since they are usually predatory in their 

 habits, some of them doubtless feed on eggs and young of 

 the insects with which they associate. They are small, slender 

 beetles, with very short wing covers, and strong biting mand- 

 ables ; are exceedingly rapid in their movements, and are usu- 



