SHORT CUTS BY BIRDS TO NECTARIES. 387 
by no means of a kind to admit the insects on which these species apparently 
mainly depend *. 
But the question naturally suggested itself: How are very definitely 
ornithophilous flowers, to whose chances of cross pollination such openings 
might often be fatal, guarded (if at all) against such attempts? This led to 
observations on Ærythrina, Leonotis, and Grevillea. 
Е. NOTE on ÆRYTuRINA. 
Му observations on two Erythrinas (А. Нитеапа, Spreng., and E. tomen- 
tosa, R. Br.) cover slightly wider ground than my remaining observations 
on ornithophilous flowers. I have accordingly, with some reluctance, decided 
to hold them over for later publication in another connection. 
I will merely state here that in their case the damage (less often successful 
than in, e. g., Canna indica or Gardenia tigrina) was inflicted not only by 
sunbirds but by widow-birds too (Coliopasser ardens, Bodd.), and that here 
again certain individual birds damaged more or less indiscriminately while 
others, that followed, utilized the damage whenever the flower’s natural 
Opening was inconvenient. 
An attempt was made to ascertain whether discrimination on the part of 
the birds resulted in a correspondingly discriminative setting of fruit. Com- 
plicating factors, as the destruction of many of the young fruits by moth- 
larvæ and probable incapacity of a peduncle to carry more than a limited 
number of fruits (the capacity varying apparently with soil, &c.), obscured 
the result ; but a clear instance of elimination was seen in each of two groups 
of trees (both Erythrina tomentosa) no less than 20 miles apart. In one tree 
in each group the next-to-open buds overhung the open flowers, obstructing 
the operations of the more indiscriminate birds. In the other trees of each 
group they tended, as is the more usual at Chirinda, to turn back. Мару of 
the overhanging buds were torn bodily off, while those that turned back were 
spared. 
The birds watched visiting the flowers of Erythrina Humeana, Spreng., 
were a Ploceid (Hyphantornis jamesoni, Sharpe), a white-eye (Zosterops 
anderssoni, Shelley), three sunbirds (Cinnyris venustus var. niasse, Reichw., 
Chalcomitra gutturalis (Linn.) Cab., and Chalcomitra kirki, Shelley), а bulbul 
(Pycnonotus layardi, Gurney), and a coly (Colius striatus var. minor, Cab.). 
The birds watched visiting the flowers of Erythrina tomentosa, R. Br. were 
five Ploceids (Sitagra ocularia, A. Sm., Hyphantornis jamesoni, Sharpe, Colio- 
passer ardens, Bodd., Estrilda astrilda (Linn.) Swains., and Estrilda kilimensis, 
* I have, however, since writing this come across some instances of far severer damage 
in the Chirinda Forest, the bill-marks suggesting that the forest bulbuls (Phyllostrophus 
milanjensis, Shelley, and Phyllostrophus flavistriatus, Sharpe) may have been the culprits. 
