Burgess.] 320 [February 27, 



some years since I described from the lithographic stones of Solen- 

 hofen. 1 



In the supplementary notes mentioned below I have said that this 

 fossil of Solenhofen, Hasseltides primigenius Weyenb., belongs to the 

 small order of the Phalangita, which in the descending system falls 

 between the Pedipalpi (scorpions) and Araneidea (true spiders), but 

 I left it undecided whether it belonged to the family Opilionidae, 

 to which belong the two other species known from the secondary 

 rocks of Solenhofen {Phalangites priscus Roth and Ph. cursor Roth), 

 or to the family Gonyleptidae. Now, however, I am convinced that 

 the Hasseltides primigenius belongs to the family Gonyleptidae, and 

 is allied to the genus Pachylus. 



Cordova (Argentine Republic), 1877. 



Section of Entomology. February 27, 1878. 

 Mr. G. Dimmock in the chair. Thirteen persons present. 

 The following paper was read : — 



TWO INTERESTING AMERICAN DlPTERA. By EdWAED BURGESS. 



I have had in my collection for several years an interesting fly, 

 taken in Springfield by Mr. George Dimmock, the true position of 

 which among those families of Diptera grouped about the Tabanidas, 

 and characterized by the complete marginal' vein of the wing and a 

 pulvilliform empodium, has been very doubtful. Like the genus Ar- 

 thropeas of Loew, 2 this form presents affinities in several directions, 

 and, like it, shows the necessity of a future remodelling of the groups 

 in question. Arthropeas was placed by Loew provisionally among 

 the Xylophagidse, and if we accept the families as they stand and 

 consider the antennal structure to be of the highest importance, it 

 must undoubtedly be referred to this family. Baron Osten Sacken, 

 whose opinions on the dipterological system are entitled to the high- 



1 Cf . Weyenbergb. Sur les insectes fossiles du calcaire lithograph, de la Baviere, 

 etc., in: Archiv. du Musee Teyler a Harlem, T. II. (1869), p. 247. 



Supplementary notes to this monograph I have given in the same "Archives," 

 T. in, and in the " Periodico Zoologico Argentino." T, I. (1874). 



2 Ent. Zeit., Stettin, xi, 504. 



