NO. 1G87. THE THOR\X OF l\I^ECT^—f<XOD<!R.\^^. 567 



13. In Aving base (202, 203) media (J/) and cubitus (Ci/) fuse 

 with base of radius (A'). Axillaries of ordinary structure (202, 203, 

 204). 



14. The jugum (202, Jii), present in lower families, is siuiply a 

 lobe of anal region of fore wing and is supported by last anal vein 



(3 A). 



15. The frenulum (204, Fr) consists of a spine or bunch of bristles 

 developed on enlarged base of costa {(') of hind wing. 



XIII. ITYMENOPTKRA. 



Sp^'cies studied. -^Cimhcx amerirana (161-lCG, wing base 205), 

 Parasiloba sp. (lG0),Tenthredinid8e; Sirex fainpennis (IGl, 171, 172, 

 Aving bases 200, 207) Siricida^; Pepsis sp. (lOS, IGO, 170, wing bases 

 208, 209) Pompilida}; Sjjhecius speciosus, Bembecida\ 



Characteristics. — 1. Pronotum {N^) attached to mesothorax (IGO, 

 163, 1G9) and but loosely connected with prothoracic pleural parts 

 (IGO, 1G2, 1G8), except in Sirex where prothoracic parts retain nor- 

 mal relations (171). 



2. Trochantin absent as a distinct sclerite in all three segments. 



3. Epimerum of prothorax rudimentary, forming merely a narrow 

 posterior marginal rim on episternum (IGO, 1G2, 1G8, 171, Epm). 



4. Mesonotum divided into three distinct divisions (160, 161, 163, 

 170, ;>5c, set. scl), first of which (psc) sometimes entirely concealed by 

 pronotum (160, N^). Scutum (161, 170, set) carries anterior notal 

 wing processes (ANP) while scutellum (scJ) carries posterior wing 

 ]n-ocesses (PNP) and axillary cords {AxC). Mesopseudonotum (160, 

 161, 1G3, 169, 170, PA\) carries large postphragma (161, 163, 170, 

 Pph) projecting downward and backward into metathorax. 



5. Metathorax well developed and of normal shape in Cimhex 

 (164) presenting all the principal pleural and tergal parts {Eps., 

 Epm., set, sel^ PN). In Parasiloba (160) parts somewhat larger, but 

 pleural suture (PaS) almost horizontal. In all higher Hymen optera 

 (Pepsis 169) the metapleurites {Epx., Epr)i) are elongate, entirely 

 fused with each other, obliterating the metapleural suture, and con- 

 tinuous with the pseudonotum {PN.^. 



6. First abdominal tergum {IT) in Parasiloba (160) somewhat 

 more separated from second abdominal tergum {I IT) than from the 

 metapseudonotum {PN._^). In Chnbcx (164) entire first abdominal 

 segment {IT) attached to posterior rim of the metathorax and but 

 loosely connected with rest of abdomen (166). In all higher families 

 {Pepsis 169) the first abdominal tergum {IT) solidly incorporated 

 into metathoracic wall and virtually a part of metathorax, the pedun- 

 cular constriction occurring betAveen it and second abdominal seg- 

 ment {I IT). This is probably the most distinctive character of the 



