50 
IMEMOIKS OF THE NATIONAL ACADEMY OP SCIENCES. 
The distribution of most of the genera and nearly each species of IN'otodontiaua is shown ou^ 
the nine plain maps accompanying this memoir. It is believed that by having a number in con- 
spicuous type, representing a distinct species, the map will both show at a glance the known 
localities where they were found and also the distribution. When the entire group has been 
discussed, we hope to x:)resent a final colored map showing the general distribution of insect life 
in North America. 
SEASONAL VARIATION. 
Almost nothing has been done on this subject, except for the butterflies by Mr. W. H. 
Edwards, whose able investigations are well known. The only facts known as regards the 
Bombyces are those stated to us b}’" Mr. Beutenmuller, who, in breeding IcMhyura aincalis^ has 
found that the summer and winter broods of this species are difterent in hue, the pale individuals 
belonging to the summer brood and the darker ones to the earlier winter brood. 
We‘ have also called attention to the cases of Drepana arcuaia and Dryopieris rosea^ first 
noticed by the late S. Lowell Elliot. Mrs. Slosson tells us that in Franconia, N. H., the early May 
brood of the Greometrid moth, Selenea Icentaria, is darker and richer in hue than those of the later 
or summer brood. 
CLIMATIC VARIATION IN THE NOTODONTID^E. 
In an essay on the general subject of climatic variation in our Monograph of Geometrid 
Moths (x)p. 58-1-589) we called attention to the changes in the size of the body, in the shape of the 
wings, and in the coloration, observed in Colorado and on the Pacific Coast, in individuals of 
species ranging across the continent. We gave a list of 27 species of Geometrid moths which 
attain a larger size as we go west, and which in some cases have longer, more pointed wings than 
individuals from the Atlantic Coast. 
Our observations on individuals of the present family have been very scanty from the lack of 
material, none of the collections I have been able to consult being rich in number of individuals;- 
also from deficiency on the labels of exact localities, and of information as to whether captures 
were made on the plains or among the mountains in a State like Colorado, and whatever is 
stated here should be regarded as merely tentative and suggestive, rather than final and 
conclusive. 
Notodontidw tchicli attain a larger size in the Gampestrian suhprovmce, indnding the Pacific Coasty 
than in the Atlantic or Appalachian and Atistroriparian suhprovmces. 
Ichthyura inornata. 
Pheosia dimidiata. 
Schizura unicornis var. conspecta. 
Cerura cinera and var. cineroides. 
Species which have longer icings in the Camiyestrian snhprovinces than in the Appalachian and 
Austroriparian. 
Schizura concinna (salicis). Cerura nivea. 
Species ichich tend to bleach out or to become paler than eastern individuals, and to lose their dark, 
markings in the Arid or Gampestrian subprovinces [including the loiclands of Galifornia), 
Gluphisia wrightii. 
Ichthyura apicalis. 
var. astorim. 
severa. 
var. formosa. Schizura unicornis. 
. var. conspecta. 
var. albofascia (Utah). Cerura cinerea. 
and var. nivea. 
It is not improbable that the Campestrian (Colorado and Utah) species of Gluphisia, such as 
G, ridenda, G, rupta and albofascia are climatic varieties of (?. septentrionis. 
Proc. Best. Soc. Nat. Hist., sxiv, ii. 491, 1890. 
