ART. 18 



NORTH AMERICAN ICHNEUMON-FLIES CUSHMAN 



10. Frons unai-med, but frequently witli a median carina that, seen fi-om above, 



muy appear as a small horn (lig. le), propodeuin without distinct 



apophyses though frequently with apical carina hif,'h (fig. 3 g and /)__ 11 



Frons with a stout horn (lig. !/■), propodeum with strong apophyses (fig. 37i). 



Polycyrtus Spinola. 



Pio. 4. — Hind Trochanter and Pemce of: 

 o. Dkrocbntrus macilentus (Crbsson) ; 

 5. Mesostenus thoracicus Cresson 



nAc. 



Fig. 5. — Fore Wing of Ackiu\stes pke- 

 TiNAx (Cresson) 



11. Hind trochautella not longer than trochanter (fig. 46), ovipositor shorter 



than body Mesostenus Gravenhorst. 



Hind trochantellu much longer than trochanter (fig. 4a), ovipositor much 

 longer than body Derocentrus Cushman. 



^ ^ ^ -0^- 



n-AcCi 



Fio. 6. — The Areolet of: a. Agonocryptds discoidaloides (Viereck) ; 5. Messa- 

 TOPORus DiscoiDALis (Cresson) ; c. Messatoporus major Cushman ; d. Mai.lo- 



CHIA AGENIOIDES ViERF.CK ; €. LiSTROGNATHUS ALBOMACDLATUS (CUESSON); f. 

 DiAPETIMORPHA ORBA (SAY) ; g. DiAPETIMORPHA INTROITA (CRESSON) ; h. CRYP- 

 TUROPSIS TEXANUS (ASHMEAD) ; t. POLYABNUS SPINAUIUS (BrULLE) \ j. MeSOS 

 TBNUS THORACICUS CrESSON ; fc. POLYCYRTUS NEGLECTUS CUSHMAN ; I. DEROCEN- 

 TRUS MACILENTUS (CrESSON) ; 111. I'OLYCYRTIDEA LIMITIS CUSHMAN ; n. ACERASTES 



PEBTiNAx (Cresson) ; o. Polistiphaga fulva (Cresson) 



12. Frons (fig. \g) with a stout horn; areolet (fig. Qm) not defined, second 

 intercubitus missing, radius, first intercubitus and recurrent very close 



together, nervellus inclivous Polycyrtidea Viereck, 



Frons mutic; areolet (fig. 6«) pentagonal in position, second intercubitus 

 missing, cubitus subobsolete beyond recurrent; nervellus reclivous. 



Acerastes, new genus. 



