126 PAINTED WARBLERS. 



middle to form anastomosing clusters (see Fig.56and compire D, section of skull or 

 Redstart with C, section of skull of Least Flycatcher, both sections from top of skull, 

 and both greatly enlarged ). In the Redstart the divisions of the walls of the skull 

 are a little farther apart than in most other warblers, but in the- Least Flycatcher 

 they are even more widely separated. 



Brain; as a consequence of the small, narrow skull we find tiie brain of the Red- 

 start also quite small and narrow. For direct comparison with the brain of the Red- 

 start I have selected that of the Black-throated Green Warbler, as both birds are of 

 about the same size and both largely woodland species. In order to present the 

 facts to the reader in the best manner I give below the ineasurements of three por- 

 tions of the brains of three species of warblers, the longest and shortest dinmters be- 

 ing given, the width first. The cerebrum is measured across both lobes. 



Measupements of Brains of Warbleps 



Cerebrum. Cerebellum. Optic Lob.s 



Redstart, | .40 by .35, | .ib by 19. | .ii b y.iQ. 



Bl ack-throated Green, | 42 by .40, | .14 by. 16, | .12 by. 19. 



Chestnut-sided, | .47 by .48, j -ij ^v - ^S' I •^~ by .16. 



A little study of the figures given will show that the small size of the brain of 

 the Redstart is due to a reduction of the cerebrum, and this is really smaller in bulk 

 than the actual measurements show for it is considerably cut away, or narrowed, on 

 the anterior portion. The cerebellum is not only proportionately larger in the Red- 

 start than in the Black-throated Green, but is actually larger by measurement, and 

 is also even larger than in the Chestnut-sided which is a considerably larger bird. 

 Accordino- to the size of the body the optic lobes in the Redstart are one one hun- 

 dredth of an inch narrower than in the Black-throated Green, but in proportion to 

 the size of the cerebrum they are at least as large as those of that species, while 

 thev are actually as large as are those of the Chestnut-sided. I have not given a fig- 

 ure of the brain of the Black-throated Green, but on page 58, Fig. 33, B and B', will 

 be found cuts of the brain of the Chestnut-sided which is about the same form; com- 

 pare with cuts of the brain of the Redstart as given in Fig. 56: K, brain from above 

 showing cerebrum, L, posterior portion showing cerebellum, M, base showing optic 

 lobes ; all of these figures are life size. If we knew nothing of the habits of the Red- 

 start the form and proportions of the parts of the brain would teach us something of 

 them. The large cerebellum indicates greater activity than in either of the two spe- 

 cies with which we have compared it; while the small cerebellum points to less intel- 

 ligence, its well developed optic lobes denote that its sight is good. The Redstart is 

 certainly n active bird with acute eyesight. Any observer will testify to the fact that 

 it is constantly darting into the air to capture insects which are often so tiny as to 

 be invisible to the unaided human eye. Yet we should not expect to find a bird as 

 intelligent that takes its prey when it is in open sight, as does the Redstart, as we 

 should in species, like the others mentioned, which are obliged to search carefully 

 among foliage for the larvae of insects, Avhich not only conceal themselves quite ex- 

 pertly, but often resemble their surroundings so closely in color that they are dif- 

 ficult to distinguish. 



Tongue, wide, thin, and horny, slightly hollowed, and with the tip provided 

 with two small tufts of rather minute bristles that, in reduced size, extend along the 



