THE PINE INVESTIGATION. 409 



Doryctes sp. Reared from pine bark infested with D. fron- 

 talis. Bark taken in July, 1892. This must be conceded a 

 doubtful parasite since it was not reared direct irora cocoons or 

 larvae found in the galleries of D. frontalis. No other beetle 

 was bred from the bark however. 



Cecidostiba dendroctoni (n. sp.) Ashrn, 1 Adults collected on 

 bark of spruce infested with D frontalis, Allegheny Moun- 

 tains, 4000 feet alt. June 22d, 1892, and reared from pine bark 

 infested with D. frontalis. Bark taken in July, '93. This is a 

 common parasite of the spruce bark-beetle, Polygraphus ruti- 

 pennis', and has also been reared by me from pupae found in 

 the liirval galleries of Tomicus cacoqraphus. 



Roptrocerus ecceptogastri Ratz. Reared from larvae asso- 

 ciated with larvae of Heydenia unica in larval mines and pupa 

 cases of D. frontalis, in scrub pine at Dellslow, W. Va., No- 

 vember llth, 1892. I have also found it to be a common par- 

 asite of Tomicus pini in white pine, Tomicus cacographus in 

 scrub pine, and Tomicus caelatus in Norway spruce. 



There are doubtless many other Hymenopterous parasites of 

 other pine bark-beetles which would quite as readily attack D. 

 frontalis. 



Of the parasites mentioned, Cecidostiba dendroctoni and 

 Roptrocerus ecceptogastri were met with most commonly, and 

 doubtless rendered considerable service in reducing the num- 

 bers of the destructive pine bark beetle. 



Thanasimus dubius Fab. Common. Adults on surface of 

 bark, and larvae in galleries and mines in bark of trees infested 

 with D. frontalis and other pine and spruce bark-beetles. Th3 

 adult feeds on the adults, and the larva on the larvae, pupae, 

 and immature of soft adults of the bark beetles. This is the 

 commonest enemy of all Scolytids which infest conifers. 



Thanasimus ( Clerus) formicarius, L. Imported from Ger- 

 many to feed upon D. frontalis, which it was observed to do 

 when liberated on trees infested with this bark beetle. 



1. Trigonoderua sp. Bull, 17, W. Va, Exp, Sta. 189L p. 102. LoQhites sp. a and d, in 

 Bull. 31, W, Va. Exp, Sta., 1893, pp, HM48 f 



