86 ILLINOIS BIOLOGICAL MONOGRAPHS [256 



EXPLANATION OF PLATE 



Mandible and Maxillae 



Fig. 256h. Hypothetical mandible. 



Fig. 257. Hypothetical maxillae. 



Fig. 258. Simulium venustum, female, cephalic aspect. 



Fig. 259. Tabanus giganteus, female, caudal aspect 



Fig. 260. Trichocera bimacula, caudal aspect. 



Fig. 261. Rhyphus punctatus, caudal aspect. 



Fig. 262. Dixa clavata, caudal aspect. 



Fig. 263. Psychoda albipennis, caudal aspect 



Fig. 264. Bibio feinoratus, caudal aspect. 



Fig. 265. Culicoidei sanguisugus, female, caudal aspect 



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



Fig. 267. Sciara varians, caudal aspect. 



Fig. 268. Rhabdophaga strobiloides, caudal aspect. 



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



Fig. 270. Chironomus ferrugineovittatus, cephalic aspect. 



Fig. 271. My das clavatus, lateral aspect 



Fig. 272. Platypesa velutina, lateral ajSpect. 



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 bicornis, portion of caudal aspect 



Fig. 278. Aphiochaeta agarici, lateral aspect. 



Fig. 279. Pipunculus cingulatus, lateral aspect 



Fig. 280. Lonchoptera lutea. 



Fig. 281. Psilocephala haemorrhoidalis, cephalic aspect 



Fig. 282. Scenopinus fenestralis. 



Fig. 283. Tabanus giganteus, male, caudal aspect 



Fig. 284. Dolichopus bifractus. 



