OF THE MOUTH PARTS OF CERTAIN INSECTS. 197 
EXPLANATION OF THE PLATES. 
The lettering of the parts, the same throughout, and the abbreviations, are as follows: ZLbr, labrum; epi, 
epipharynx (the two sometimes combined as lbr-ept) ; md, mandible; car, cardo; st, stipes; pfr, palpifer; mp, 
maxillary palpus; gal, galea; sg, subgalea; lac, lacinia; dig, digitus; sm, submentum; m, mentum; gl, ligula or 
glossa ; par, paraglossa ; Ip, labial palpi; Ayp, hypopharynx. 
ray 
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SOW ea Pw pp 
Plate I. 
Buffalo gnat. 1¢, galear structures with palpi attached ; 19, labial structures ; 1¢, lacinia and palpifer of 
Simulium from Aldrich ; 14, labrum and labium of Simulium from Aldrich ; 1¢, transverse section through 
middle of mouth of Buffalo gnat. 
Simulium from Anglesea, N. J. 
2, the maxillary structures in their actual relation to each other ; 2%, 
transverse section of mouth parts toward the base of subgalea. 
Mouth parts of Hristalis tenaz. 34, transverse section of same at the middle of subgalea. 
Copris carolina, epipharynx. 
Mouth structures of Tipula sp.; 5¢, the chitinous parts of the same. 
Copris carolina ; labial structures dissected out and seen from side. 
Copris carolina ; chitinous part of under side of head. 
Copris carolina ; mandible with the sclerites named and homologized. 
Andrena vicina ; labial structures, with part of epipharynx attached. 
Libellula sp. a, the epipharynx ; b, the hypopharynx. 
Stomoxys calcitrans ; transverse section through the middle of the ligula. 
Mouth parts of Huparyphus bellus. 
Maxillary structure of Leptis sp. 
Palpifer of Stratiomyia. 
Palpifer of Hulonchus tristis. 
Palpifer of Hmpis spectabilis. 
Plate I. 
Palpifer of Spharophoria cylindrica. 
Palpifer of Bombylius. 
Palpifer of Anthrax. 
Palpifer of Chrysops vittatus. 
Palpifer of Simulium. 
Palpifer of Lucillia. 
Palpifer of Calléphora. 
Palpifer of Stomozys. 
Figs. 10 to 12 inclusive were accidentally reversed in making up the plate. 
Mouth parts of Hmpis spectabilis. 
134, elongated head structure at tip, showing mandibles and epipharynx ; 
13, transverse section at middle of subgalea. 
Mouth parts of Chrysops vittatus showing maxillary structures attached together. 144, the lacinia ; 14°, pal- 
pifer and palpus ; 14¢, transverse section at middle of galea. 
Labial structures of Xenoglossa pruinosa. 4, transverse section at about middle. 
Labial structures of Periplaneta orientalis. 
Maxillary structures of Hermetia mucens. 
Mouth structures of Polistes metricus. 184, ligula, paraglossa and mouth opening ; 18°, labium as a whole, 
with epipharynx attached ; 18¢, maxilla. 
Maxilla of Olfersia. 194, seen from front; 19, seen from behind or below. 
