REVIEWS OF RECENT LITERATURE. 737 
cultivated form (Japan rose), with flowers all sterile and showy. On 
the former the insect visitors were not numerous, and were limited 
to pollen-eating Diptera and Hymenoptera. These alight from the 
first upon the fertile flowers, passing directly over the sterile ones, 
making few even slight errors (Hymenoptera, one to seventy-seven 
visits ; Diptera, one to eighteen visits), making still fewer obviously 
complete mistakes. In the cultivated form the flowers are neglected 
altogether, or, retaining somewhere occasional anthers, attract a few 
Syrphus flies directly to these. 
Having shown that the “ vexillary ” peripheral flowers are almost 
entirely disregarded by insects near at hand, M. Plateau proceeds to 
show that they do not exercise any special attraction at a distance, 
citing two facts in evidence: (1) that the peripheral flowers open 
several days before the fertile, and remain fresh for several days 
after the fertile have faded; and (2) that the very showy cultivated 
flowers, lacking pollen and perfume, attract no insects. He shows 
also that insects do not learn by individual experimentation the 
nature of the two softs of flowers. Then he objects to the idea of 
their possessing hereditary instinctive knowledge on the very insuf- 
ficient ground of analogy with birds which have to learn to recognize 
inedible larve by individual experience. 
The search for a basis in observable facts lor the theories of color- 
ation long current is certainly most desirable ; and while every one 
will acknowledge the value of the facts discovered, one may still 
think that they do not fully justify the general conclusion, that these 
so-called “ vexillary ” organs have no right to be so considered. For 
if one fully agree with M. Plateau, that the fertilization of the flowers 
in question “would not suffer from the absence of these parts” at 
the present time, still the old theory would serve to explain their 
origin in the past; and the fact that mistakes are still made is not to 
be disregarded. 
The old explanation of the coloration of bracts, etc., has been so 
satisfactory and so applicable to many facts of different kinds, that 
in absence of any substitute one may feel reluctant to abandon it, 
especially while our knowledge of the nature of the apperceptions of 
insects is so meager that we may hardly judge by what means they 
discover the flowers. That insects should make mistakes is no part . 
of the theory ; it does not assume that the external showy parts should 
delay visitors or divert them from their proper course to the pollen or, 
the nectar. LGN, 
