March, 1913-] PROCEEDINGS OF THE SOCIETY. 89 



the modified J mouth parts of blood-sucking species, the expanded front legs 

 of (^ Platychiriis, the expanded front and middle legs of (^ Pyrophaena, the 

 expanded first tarsal joint of (^ Simulidae ; and the color differences frequently- 

 observed in the sexes, the male usually being the more highly pigmented, its 

 yellow markings when present being larger and its metallic color more pro- 

 nounced. The hairs also, he said, were usually better developed in the male, 

 the spinous hairs stronger, the bristles of the antennae and the hairs about the 

 eyes usually longer. These differences were, however, not without exceptions, 

 and often were much more marked in one species than in others. The append- 

 ages of the legs of (^ Dolichopodidse and their amorous dances, described by 

 Aldrich, were mentioned as well as the male modifications of the posterior 

 ventral segment. In closing, Dr. Osburn referred to the various efforts that 

 had been made to explain sexual dimorphism since Darwin's conception of 

 sexual selection became in part ncessarily modified ; the classification by Cun- 

 ningham of the structures involved into functions of combat, allurement and 

 the different conditions to which the two sexes are exposed ; the theory of 

 Morgan that such structures are in part the product of sex-linked heredity and 

 so appear in only one sex, as foreshadowed by Geddes and Thompson in their 

 expression " outcrops of a male as opposed to a female constitution." 



Specimens illustrating the various structures and color differences men- 

 tioned were exhibited and further explanations were given during the exhibition. 



Dr. Osburn's paper was discussed by Messrs. Angell, Davis and Bagg, and 

 in reply to their questions Dr. Osburn said that in the absence of colonial 

 forms there was no possibility of neuters existing, but that, as suggested by 

 Mr. Davis, undeveloped individuals, as in Membracidae, might occur, and one 

 would then expect to find intermediate conditions of color. The secondary 

 male characters would naturally come on with the development of sexual ma- 

 turity. Dr. Osburn also in this connection referred to the higher rate of oxida- 

 tion stated by Geddes and Thompson to be normal in males of all species. 



In reply to Mr. Bagg's question, Dr. Osburn said that the attitude of 

 workers in regard to scientific names for the experimental species resulting 

 from the work of students of evolution and mutation varied ; and though such 

 had been applied in some cases to Lepidoptera, he would personally be opposed 

 to such a course. 



Mr. Sleight exhibited specimens of inflated larvae resting in natural poses 

 on the leaves of the food plant, prepared by Mr. Hallinan and said the process 

 consisted in inflating as usual, then filling the larvae with sand so as to permit 

 of posing them without damage, then drying and pouring out the sand. 



Mr. Davis, referring to the unusual warmth of January 6, exhibited a speci- 

 men of the moth Platypena scabra, found flying in front of his home on Stuy- 

 vesant Place, Staten Island. 



During the service of refreshments Dr. Lucas read extracts from " The 

 Book of Bugs," by Harvey Sutherland, humorously detailing the estimable and 

 other characters of cockroaches and several members contributed notes on the 

 entertaining features of entomology. 



