RECENT LITERATURE. 255 
RECENT LITERATURE. 
A Monograph of the Jumping Plant-lice or Psylude of the New 
World. By Davip L. Crawrorp. Pp. 182; plates 30. Smith- 
sonian Institution, United States National Museum. Bulletin 
85. Washington. 1914. 
THe author finding that classification of the Psyllide on wing 
venation alone was unsatisfactory, placing as it does closely related 
species in different genera and even subfamilies, presents a new 
system based largely on a study of structural characters other than 
venation. 
The one hundred and seventy-five species in twenty-nine genera 
here enumerated and described are arranged under six subfamily 
headings, in the following sequence :— 
Subfamily Livine. 
Tribe Liviini ... ... 1 genus (Lzvia), 5 species. 
» Aphalarini ... 2 genera, 22 species. 
Subfamily Pauropsylline .... .... 3 genera, 15 species. 
if Carsidarine ... ... ... 4 genera, 13 species. 
es Ceriacreminz ... . 1 genus, 2 species. 
is Triozing... ... ... ... 8 genera, 44 species. 
ie Psylline. 
Tribe Pachypsyllini... 3 genera, 9 species. 
»  Huphyllurini ... 2 genera, 6 species. 
»  Arytainini ... 3 genera, 18 species. 
7 eesyllmt a... -2tBenera, 41 species: 
Among other matters of interest treated in the introductory 
pages (1-18), morphology is discussed in considerable detail. 
An extensive bibliography is given. 
Pond Problems. By H. EK. Unwin, M.Sc. Pp.xvi+119. (Cambridge 
Nature Study Series.) Cambridge: University Press. 1914. 
Tuts book supplies a series of lessons on Pond Life, intended for the 
lower forms of Secondary Schools and upper standards of Elementary 
Schools. It is above the average of such books, and we venture 
to think that much of the work would be suitable for higher forms 
in the Secondary Schools (if time could be found for it), and that any 
entomologist, especially one who is given overmuch to collecting 
simply, might study it with advantage. The aim of the series of 
practical lessons and demonstrations is really to give some ideas 
from actual contact with Nature ‘ about environment, natural selec- 
tion, and evolution.’ After showing how material should be obtained, 
and making quite clear what an insect is, our author states that 
“insects are really land animals,” even though now in a compara- 
tively few cases they may pass part of their life in the water. The 
main object of the remaining lessons is, by practical observation and 
experiment, to show how the adaptation to their new surroundings 
is managed. The work concludes with useful appendices on material, 
apparatus, the microscope and the making of microscope-slides, and 
a short bibliography. The book, which is well got up, is illustrated 
by forty-seven good figures, all, except two, from the author’s draw- 
