1871.] 207 • [Annual Report. 



Mr. Charles S. Minot exhibited specimens of the so called 

 Tarantula of California, (the trap-door spider, 3Iygale Sent- 

 zii Gir.) and its nest, from aluminous soil, three or four inches 

 deep, lined with two layers of silk. Also specimens of Pom- 

 pilus formosus, a wasp which attacks and destroys the spider. 

 He gave an interesting account of the manner in which 

 the wasp paralyzes or renders its victim helpless. This spe- 

 cies is very sensitive to odors, many individuals being fre- 

 quently attracted to the spot where a spider is being victim- 

 ized. 



Mr. Edward Burgess described and figured the peculiar 

 sexual markings of some of the Diptera, Dolichopus pugil 

 Loew, and other species of this genus, showing the variations 

 in the feet, antennae, and wings ; these in several species are 

 rounded in the female but squarely cut in the male. He 

 called attention to the views of Darwin in his recent work 

 on the selection of species, citing the Dipterous family JBibi- 

 onidce as affording very interesting characteristics. 



Mr. S. E. Sargent, of Boston, was nominated for member- 

 ship in the Section. 



Annual Meeting, May 3, 1871. 

 The President in the chair. Thirty-nine members present. 



Prof. Alpheus Hyatt presented the following report of the 

 Custodian for the present year. 



My predecessor, the distinguished entomologist, Mr. Sam- 

 uel H. Scudder, held three offices, Custodian, Secretary and 

 Librarian ; these at the last annual election were divided, 

 Mr. J. A. Swan being selected as Secretary and Librarian. 

 This division places the Museum more especially in my 

 charge. 



