938 General Notes. 
This work was at first intended to embrace only the butterflies 
known to occur in New England or its immediate confines ; but it has 
been extended so as to include in its descriptions and histories some 
account of all the butterflies of North America, east of the Missis- 
sippi, excepting such as are found only in the uasettled parts of 
anada, or south of Kentucky and Virginia. 
Not only every species, but also every genus, tribe, sub-family, 
and family, are described and discussed with a fulness never before 
attempted, except in individual cases. The descriptions include in 
each instance not merely the perfect form, but when possible, the 
eggs, the caterpillar at birth and in the succeeding stages, and 
the chrysalis, together with the distribution, life-history, habits, and 
environments of the insects. A great accumulation of new facts and 
observations are embodied. Analytical tables applicable to every 
stage are used wherever possible. 
Over seventy distinct execursuses, distributed throughout the 
work, discuss separately all the interesting problems which arise in 
the study of butterflies (whether of distribution, structure, history, 
or relation to the outer world), in themselves forming a complete 
treatise on the life of these insects. Judging by the fragment of 
the excursus devoted to dimorphism and polymorphism which is 
given in the prospectus, this part of the work will be of the highest 
interest to those who study entomology in a scholarly way, whatever 
their specialty. 
very page of this treatise bears evidence of the wonderful 
amount of pains-taking labor devoted to its preparation. For 
twenty years the author has been at work upon it ; and for the last 
eight years it has received his undivided attention. No one else 
has brought to the study of this group of insects more scholarly 
attainments, nor has achieved such magnificient results. We trust 
that the work will receive the recognition that it deserves. 
VISION OF CATERPILLARS AND ADULT Insgcrs.—Prof. F. 
Plateau continues his researches on the powers of vision by an m- 
vestigation of caterpillars and of the frontal ocelli of adult insects. 
1) He made a series of experiments and observations on iL 
caterpillars of fifteen species of Lepidoptera, and obtained the pe 
lowing results: (a) The eyes of caterpillars have a more importan 
rôle than that of simply distinguishing between light and darkness. 
They really see, though badly. (b) The distance of distinct visio” 
is short, and usually about a centimetre. (c) At greater distances 
caterpillars can perceive large masses, but do not discern mre 
nature. (d) They only perceive the movements of bodies ee 
the limits of distinct vision. (e) Tactile hairs present on : 
anterior segments of many forms are of much sensory importance. 
‘ Bull. Acad, R. Sci. Belg. xv. (1888), pp. 28-91. 
