50 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



The distribution of most of the genera and nearly each species of Notodontians is shown on 

 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 present a final colored map sliowing 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 

 Bond)yces are those stated to us by Mr. Beuteumiiller. who, in breeding Ichthyura (q)icalis, has 

 found that the summer and winter broods of this species are ditferent 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 arcuata and Dryopteris rosea, first 

 noticed by the late S. Lowell Elliot. Mrs. Slosson tells us that in Pi-anconia, N. H., the early May 

 brood of the Geometrid moth, SdcHea kentaria, is darker and richer in hue than those of the later 

 or summer brood. 



CLIMATIC VARIATION IN THE NOTODONTID^i:. 



In an essay on the general subject of climatic variation in our Monograph of Geometrid 

 Moths (pp. 5SJ:-.")S9) we called attention to tlie changes in the size of the body, in the shape of the 

 wings, and in the coloration, observed in Colorado and (m 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 whicli in some cases have longer, more pointed wings than 

 individuals from the Atlantic Coast. 



( )ur observations on individuals of the present family have been very scanty from the lack of 

 material, n(me 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. 



NotodoHt'uhv iciiich attain a Jar(/cr size in the Campestrian siibprorinee, includinf/ the racific Coast, 

 than in the Atlantic or Appalachian and Austroriparian suhprorinces. 



Ichtliyura iuoimata. Schizura unicornis var. conspecta. 



Pheosia dimidiata. Cerura cinera and var. cineroides. 



Species ichich hare longer irinf/s in the Campestrian suhprorinces than in the Appalachian and 



.lustroriparian. 



Schizura concinna (salicis). Cerura nivea. 



Species irhich tend to bleach out or to become paler than eastern individuals, and to lose their dark 

 markings in the Arid or Campestrian suhprorinces (including the lowlands of California). 



Gluphisia wrightii. Ichthyura apicalis. 



var. astoriai. 

 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 Oluphisia, such as 

 G. ridenda, G. rupta and albofascia are climatic varieties of G. septcntrionis. 



' Proc. Boat. Soc. Nat. Hist., xxiv, p. 491, 1890. 



