86 ILLINOIS BIOLOGICAL MONOGRAPHS [256. 



EXPLANATION OF PLATE 



Mandible and Maxillae 



Fig. 256h. Hypothetical mandible. 



Fig. 257. Hypothetical maxillae. 



Fig. 258. Siiiiuliuiii venustuin, female, cephalic aspect. 



Fig. 259. Tahaniis giganteus, female, caudal aspect. 



Fig. 260. Trichocera biinacula, caudal aspect. 



Fig. 261. Rhyphus ptinciatus, caudal aspect. 



Fig. 262. Dixa clavata, caudal aspect. 



Fig. 263. Psychoda albipennis, caudal aspect. 



Fig. 264. Bihio feinoratus, caudal aspect. 



Fig. 265. CtiUcoides sanguisugns, female, caudal aspect. 



Fig. 266. Psorophora ciliata, female and male, caudal aspect. 



Fig. 267. Sciara varians, caudal aspect. 



Fig. 268. Rhabdophaga strohiloides, caudal aspect. 



Fig. 269. Bibiocephala elegantula, female, caudal aspect. 



Fig. 270. Chironoiuus ferrngineovittatus, cephalic aspect. 



Fig. 271. My das clavatus, lateral aspect. 



Fig. 272. Platypcza velutina, lateral aspect. 



Fig. 273. Stratiomyia apicula, cephalic aspect. 



Fig. 274. Empis clausa, lateral aspect. 



Fig. 275. Leptis vertebrata, caudal aspect. 



Fig. 276. Promachus vertebratus, caudal aspect. 



Fig. 277. Tipula bicortiis, portion of caudal aspect. 



Fig. 278. Aphiochacta agarici, lateral aspect. 



Fig. 279. Pipimculns cingulatus, lateral aspect. 



Fig. 280. Loiichoptera lutea. 



Fig. 281. Psiloccphala hacmorrhoidalis, cephalic aspect. 



Fig. 282. Scenopinus fenestralis. 



Fig. 283. Tabanus giganteus, male, caudal aspect. 



Fig. 284. Dolichopus bifractus. 



