216 ENTOMOLOGICAL NEWS f July, '22 



strcnitus proves this species to be distinct from both B. polaris 

 and B. kincaidii. Unfortunately museum pests have injured 

 the internal abdominal structures of this male, but enough of 

 the gen.italia and inner spatha remain to establish the validity 

 of the species. The apex of the inner spatha of B. strenuns 

 does not end in a conspicuous triangular projection. Instead 

 it is somewhat blunt and trilobed, the central lobe being larger 

 than either of the two lateral lobes. In some respects the 

 inner spatha is similar in outline to Sladen's figure of the inner 

 spatha of B. neoborciis (Sladen), a species recently described 

 from Bernard Harbour, Northwest Territories, in the Report 

 <>i the Canadian Arctic Expedition. In this latter species, how- 

 ever, the lateral angles of the apex of the inner spatha are 

 sharply pointed and the extreme apex or middle portion is 

 blunt and slightly curved inward. 



The shape of the inner spatha of B. kincaidii distinctly sep- 

 arates it from B. hyperboreus and B. kirbycllits, the only other 

 described American species of the Kirbyellus Group not already 

 discussed in the systematic portion of this paper. 



The University of Michigan- Williamson Expedition to Brazil. 



The expedition remained at Villa Martinho (see this volume of the 

 NEWS, page 186) until April 9, when they went by launch upstream to 

 Villa Bella, Bolivia, on the point of land at the junction of the Beni 

 and Mamore rivers to form the Madeira, and thence four hours up the 

 Rio Beni to Cashuela Espcranza. This little town of 200 to 300 people 

 is in the Provincia de Vaca Diez, Bolivia, at the falls of the Rio Beni. 

 It is the headquarters of Suarez Brothers, the rubber kings of the dis- 

 trict, and due to their wealth the town has a good hotel, ice plant, elec- 

 tric light plant, etc. ; it is built on granite rocks on the right bank of the 

 river. The falls were about 7 feet high at the time of the party's visit; 

 they are said to be 15 feet high when the stream is at low water. On 

 April 12 it was noted that the Beni had fallen about 7 teet liom tlm 

 year's high water mark. 



At Villa Martinho on March 31, it is recorded that "little gnats, sand 

 Hies and other pestiferous insects abounded." Wasps, bees and spiders 

 were abundant in the woods at Cashuela Esperanza on April 12 and 

 following days. From the latter place collections were made also along 

 the Yata river trail. On April 15, Mr. J. H. Williamson was taken 

 with malaria, wherefore he went down stream to Candelaria where is a 

 hospital in which he recovered in about ten days. Returning to Porto 

 Velho collecting was resumed on April 25. Both at Villa Martinho and 

 at Cashuela Esperanza there was much rain. On April 25 their Odonata 

 were estimated at 50'.)S specimens of 128 species. (From Mr. Jesse 

 H. Williamson's letters and "log.") 



