OF WASHINGTON. 419 



character of the egg is an expression of a morphological factor 

 and undoubtedly the variation in eggs has been brought about 

 by a process of natural selection since the perpetuation of the 

 species depends to^a greater or less extent upon the immunity of 

 the egg stage from destruction by natural enemies or other 

 causes. 



The subject of insect excrements having been introduced, the 

 discussion took somewhat the same range as in the meeting of 

 December 3, 1896 (see Proceedings, Vol. IV, pp. 73-75). 



Mr. Matthis considered that the relatively slight variation in 

 the form of the excreta of insects was to be expected since the 

 excreta bear no vital relation to the perpetuation of the species as 

 do the eggs, in which there is very great variation. 



Dr. Dyar, however, called attention to the larval cases or 

 South American lepidopterous insects of the genera Pesophera 

 and Cicinnus in which the excreta serve as a larval protection 

 and are modified to suit the conditions thus showing that excreta 

 may bear a pronounced relation to the existence of the species. 



Dr. Gill spoke of the work of Valenciennes and Fremy on the 

 eggs of animals, in which the eggs of insects receive some 

 consideration. 



JANUARY 4, 1900. 



The 1 48th regular meeting was held at the residence of Dr. 

 Harrison G. Dyar, 1512 2ist street N.W. 



President Gill in the chair, and Messrs. Waite, Matthis, Mar- 

 latt, Motter, Ashmead, Caudell, Schoenborn, Busck, Chittenden, 

 and Dyar, active members, and Kotinsky, visitor, present. 



Mr. Jacob Kotinsky was duly elected to membership by the 

 Society. 



Under the head of u Exhibition of Specimens and Short 

 Notes," Dr. Dyar exhibited material illustrating the life-history 

 of the very remarkable social butterfly (Eucheira socialis West- 

 wood) sent to the Museum recently by Dr. Alfredo Duges, Gua 

 najuato, Mexico. The exhibited material consisted of two of the 

 communal larval cases, one of which was cut open to show the 

 mass of pupal shells contained within it, and also inflated exam- 



