REVIEWS. 239 
collecting of insects for cabinet specimens. It will be urged that 
to succeed in these investigations the observer should live in the 
country and have leisure time at command. ‘This is by no means 
necessary, for nearly all who study Entomology from a point of 
view beyond mere collecting, live in localities sufficiently suburban 
to carry on some observations of value. 
“ Theoretically the diary should begin the day after the winter solstice 
(i.e, December 22nd), but in our latitudes the climate lags behind the 
sun’s movements. .... The middle of February, St. Valentine’s Day, 
may be accepted as the beginning of the biological year, and the diary 
should be kept round the year from that time.” 
Preceding the diary proper is a very interesting Introduction, 
the thirty-two pages of which will be found well worth reading, 
including the Preface. Even if disinclined to encounter the tie 
of regular observations necessary for the successful results to be 
obtained by this system, the reader will find much in this Intro- 
duction for thoughtful consideration. 
At the beginning is a coloured map, of very great interest, 
and it is only to be regretted that the observations hitherto made 
extend over such comparatively small area. The map represents 
a ‘spring chart,” constructed for April flowering plants on the 
European continent. By the coloured patches we see at a glance 
the relative values of various localities as to whether “ late” or 
“ early,’ and it will surprise many of our readers to find that the 
Devonshire south coast is equal with the north-west coast of 
Italy in the flowering time of the same plants. The map, however, 
is still very incomplete in localities where observations could have 
been taken, though enough is shown to prove its value. If we 
can follow the same lines of observation with regard to insects, 
a map showing the appearance of any certain group of species 
would prove of the greatest value in suggesting solutions for 
problems at present conspicuous for their darkness and obscurity. 
Mr. Roberts is much to be congratulated upon the first issue 
of what may be playfully called a “ Nature’s Birth-day Book,” 
and we feel quite satisfied that as the work becomes better 
understood and appreciated, its adoption, with perhaps some 
slight modification, will become general. 
It is hardly worth while to refer to certain apparent incon- 
gruities in the compilation of the pages of the diary, such as the 
