410 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no 



are grouped on certain raised areas ; the hypopharynx has numerous 

 small spine-like projections; the antenna is disc-shaped with the 

 circumference lightly sclerotized in some genera, and several sensilla 

 may be visible in the central part of the antenna; the atrium of the 

 spiracle is broad and shallow and the closing apparatus is close to the 

 atrium; the skin is relatively smooth and has smaU setae. 



Larval Key 



1. Hypostomal spur with lightly sclerotized lateral expansion . . Xanthopimpla 

 Hypostomal spur without lightly sclerotized lateral expansion 2 



2. Hypostoma approximately equal in length to blade of mandible . Apechthis 

 Hypostoma much shorter than blade of mandible 3 



3. Stipital sclerite much shorter than blade of mandible Itoplectis 



Stipital sclerite approximately equal in length to blade of mandible ... 4 



4. Broadened (ventral) part of labial sclerite about as broad as long and not 



pointed ventrally Pimpla 



Broadened (ventral) part of labial sclerite longer than wide and pointed 

 ventrally Echthroniorpha 



Genus Pimpla. — P. aequalis Provancher (fig. 6a) and P. inflatus 

 Townes have been examined. P. instigator (Fabricius) is figured by 

 Beirne (1941) and by Meyer (1922), P. luctunosa Smith by Itawa 

 (1950), P. turionellae (Linnaeus) by Thorpe (1930), Silvestri (1941), 

 and Beirne (1943), and Pimpla sp. by Beirne (1942). 



Genus Apechthis. — A. coinpunctor (Linnaeus) (fig. 6b) has been 

 examined. This species is figured by Beirne (1941). 



Genus Itoplectis. — ^The species of this genus may be primary or 

 secondary parasites. Professor Varley (in litt.) informs me that 

 /. maculator (Fabricius) appears to be more often a primary parasite 

 on Tortrix and other species, although sometimes a secondary para- 

 site. /. hehrensii (Cresson) (fig. 7b) and /. conquisitor (Say) have 

 been examined. /. alternans (Gravenhorst) is figured by Morris, 

 Cameron, and Jepson (1937), /. olivalis Thomson by Beirne (1941), 

 and Itoplectis sp. by Snodgrass (1935). Morris, Cameron, and Jepson 

 (1937) state that the inner aspects of the teeth of /. alternans are 

 armed with bristles. Teeth have not been recorded on the blade of 

 the mandible in any other species of this tribe. These authors studied 

 this species as a primary parasite of Diprion. It oviposited on pre- 

 pupae and pupae within the host cocoon and fed externally. All 

 other genera of the Pimplini appear to be endoparasites. 



Genus Echthromorpha. — E. insidiator (Smith) and E. notulatoria 

 (Fabricius) (fig. 7c) have been examined. E. formosa (Smith) is 

 figured by Beirne (1941). 



Genus Xanthojnmpla. — The broad and lightly sclerotized hyposto- 

 mal spur and the lightly sclerotized epistoma are characteristic of this 

 genus. The stipital sclerite is short and fused with the hypostomal 



