OF WASHINGTON. 311 



Dr. Howard stated that while the conclusions of the U. S. 

 Army Commission on the subject of yellow fever were very 

 generally accepted by the physicians of Central and South Amer 

 ica, no corroborative experiments have been made until very 

 recently. Much general incredulity has been felt in Brazil, but 

 in a letter just received from Dr. Adolpho Lutz, of Sao Paulo, 

 an account is given of experiments in which there were three 

 positive results, the mosquitoes having been captured in an unin- 

 fected place, taken -to the city, allowed to bite yellow fever 

 patients and then carried to an uninfected place and allowed to 

 bite non-immunes. These experiments have been accepted as 

 conclusive and Brazilian incredulity has been removed. 



Prof. Uhler mentioned the fact that mosquitoes had been 

 introduced at Buena Vista, in the mountains of western Mary 

 land, by transportation in freight cars, and that they were now 

 breeding abundantly in an ice pond which has been made there. 



Dr. Dyar then read portions of a systematic paper submitted 

 for publication by Prof. John B. Smith. The paper is as follows : 



A REVISION OF THE BOREAL-AMERICAN SPECIES OF 

 NONAGRIA Ochs. 



By JOHN B, SMITH, Sc.D. 



The species of this genus are poorly represented in American 

 collections, and are, as a rule, uncertainly named. The adults 

 are rarely taken by ordinary methods of collecting, and there is 

 usually a great dearth of males : of Iceta, for instance, I know of 

 only one $ example in all the collections seen. Several collec 

 tors have bred small series, and there seems to be no particular 

 difficulty in obtaining adults in this way ; but even in bred series 

 females seem to be in the majority so far as I have been able to 

 find. 



The head is not prominent, yet scarcely retracted ; moderate in 

 size ; front produced into a long, pointed process, more or less 

 carinate, the sides somewhat explanate, varying in the species, 

 the tip sometimes notched. As a rule the straight, hairy frontal 

 vestiture conceals all save the extreme tip of this process, and the 

 superficial appearance is that of a pointed hair tuft. The eyes . 

 are of good size, round, or nearly so, not protuberant, naked, 

 without lashes or fringes. Palpi moderate, extending to the tip 

 of the frontal process, vestiture of the second joint somewhat 

 divergent, the third varying a little in its proportion to the sec- 



