PROC. ENT. SOC. WASH., VOL. 22, NO. I, JAN., 1920 



Protergum about as wide as long, not differentiated from epipleurum at 

 sides; presternal plate of prothorax elliptical, distinct; presternal ring well- 

 defined on mesothorax and metathorax, former bearing spiracle; hypopleural 

 chitinizations very narrow line-like, the prehypopleural stronger; hypo- 

 pleural suture distinct, bearing coiidyle of coxa. Legs strong, about as long 

 as width of body, five-jointed, coxa large, conical widely separated; tro- 

 chanter short, femur about equaling tibia, tarsus shaped as a flattened claw. 



Segments uniformly chitinized, or slightly heavier on tergum which is 

 entire and bearing anteriorly a transverse, curved, dentate carina; epipleurum 

 slightly protuberant; hypopleurum less so; sternum laterally bearing two 

 faint longitudinal impressions below coxal lobe. Ninth abdominal segment 

 terminal, with tergum heavily chitinized and bearing two strongly recurved un- 

 jointed cerci, the latter having between a deep cylindrical pit; tenth wart- 

 like, ventral, having several small projecting papillae. Spiracles annular, 

 bifore, a little larger than ocelli. 



Pupa. Form as Ditoma, head concealed beneath prothorax; latter elong- 

 ate, rectangular bearing four tubercles on anterior margin, the median two 

 larger, lateral margins multidentate, with setiferous teeth; scutellum of 

 mesothorax oval; abdominal terga bearing one or two lateral setiferous 

 papillae and also one on epipleurum; last tergum bearing two strongly re- 

 curved chitinous points. 



Described from specimens, Hopk. U. S. No. 11872y, collected 

 by the writer at East Falls Church, Va., under bark of dead pine 

 log containing developing Scolytid larvae. 



They feed under the bark of a variety of coniferous trees and 

 are usually found after the inner bark has been considerably 

 macerated by other larvae. Very young larvae have been col- 

 lected and reared in confinement and they feed entirely on this 

 vegetable tissue. The pupal cell consists of a small oval enlarge- 

 ment in this macerated bark. 



Ditoma crenata F. 1 



Luri'ti. Similar to Auloniiim tuberculatum in all essential characters, but 

 the body is slightly more depressed, the terga lack the transverse carina of 

 asperities, and the ninth tergum is not heavily chitinized, but bears two slen- 

 der, recurved cerci and a shallow pit between them. The largest specimen 

 measures 5'/2 mm. long. 



Pupa. Similar to A. tiiberciilntiiiii, except by the arrangements of papillae 

 on margin of r)ronotum, and cerci not strongly recurved. 



Described from two larvae and one pupa in the U. S. N. M. 

 collection. One larva from Dr. Meinert from the Zoo. Mus., 

 Copenhagen, Denmark; one larva and pupa from E. C. Rosen- 

 berg, Copenhagen, Denmark. The latter were collected under 



1 This larva has been described by Ferris Insects du Pin Maritime, 1853. 



