394 
VIREOS 
FAMILY VIREONIMJ. VIREOS 
GENUS VIREO. 
General Characters. — Bill similar to that of the shrikes, distinctly 
hooked and notched at tip ; rictal bristles conspicuous; wings equal to or 
longer than tail; tail nearly even ; claws stout, strongly curved; side toes 
unequal in length. 
KEY TO ADULTS. 
1. Head strikingly marked. 
2. Lores and orbital ring white in sharp contrast to gray or black of 
head. 
3. Top and sides of head black, atricapillus, p. 397. 
Fig. 485. 
3'. Top and sides of head gray. 
4. Back gray. Southern Rocky Mountain region. 
plumbeus, p. 397. 
4'. Back olive green. 
5. Brighter olive green. Eastern United States. 
solitarius, p. 396. 
5'. Duller olive green. 
Western United States, 
cassinii, p. 396. 
2'. Lores and orbital ring not white in sharp contrast to 
head. 
3. Sides and flanks tinged with olive gray. 
olivaceus, p. 395. 
Fig. 48G. 
Fig. 487. 
3'. Sides and flanks bright olive yellow . . . flavoviridis, p. 395. 
1 . Head not strikingly marked. 
2. Upper parts gray. Western Texas to southern California. 
vicinior, p. 400. 
2'. Upper parts bright olive green or tinged with olive. 
3. Upper parts bright olive green. 
4. Larger and brighter . noveboracensis, p. 398. 
4'. Smaller and duller. Rio Grande Valley . . micrus, p. 399. 
3'. Upper parts tinged with olive green. 
4. Wings unmarked. gilvus, p. 395. 
4'. Wings marked with white. Fig. 488. 
5. Wing about 2.18. 
6. Wing with two distinct bands. Mississippi Valley and Plains, 
bellii, p. 399. 
6'. Wing usually with only one band. Arizona and California. 
pusillus, p. 400. 
5'. Wing about 2.50. 
6. Wing bars white. 
