0. H. TYLER TO WIST SEND — BIOGEOGRAPHY OE MEXICO, ETC. ?1 
3. Nausig aster geminata Towns, n. sp. — Beeville and Kenedy, Tex- 
as. Angnst 30 to September 14. On flowers of Parthenium hystero- 
phorus L. This is included, though not from the Rio Grande. 
4. Eupeodes volucris OS. — May 2. A distinctly Upper Sonoran spe- 
cies. 
5. Baccha clavata Fab. — May 24. A Neotropical species, extending 
into the Upper Sonoran of New Mexico along the Rio Grande Valley as 
far up as Albuquerque. 
6. Baccha tropicalis Towns, n. sp. — June 21 to 25. On flowers of 
Clematis drummondiiJV. & G. and Monardia clinopodioides Gray. This 
species belongs to a Neotropical group, occurring from Brazil to the low- 
lands of Mexico. 
7. Volucella esuriens var. violacea Say. — From San Miguel, Tamauli- 
pas, to the coast at Point Isabel, Texas. April 7 to July 14. This spe- 
cies was found to be very abundant in the palmetto hammocks below 
Brownsville, where it occurred in large companies, hovering in the air 
high up amongst the tops of the palmettos, the various individuals dart- 
ing independently here and there, but continually hovering. I have 
taken this same fly on the bare and rocky summit of San Francisco 
Mountain, in Arizona, at an elevation above sea level of nearly 13,000 
feet. It ranges from the Boreal to the Neotropical. 
8. Volucella tamaulipana Towns, n. sp. — June 24 to July 3. On 
flowers of Lippia lanceolata Michx. Belongs to a large Upper and Lower 
Sonoran group; more allied to the forms of the group found in the Lower 
Sonoran. 
9. Eristalis furcatus Wd. — June 24. A Neotropical species, ranging 
from Argentina and Brazil to tropical Mexico. 
10. Eristalis tricolor Jaenn. — June 16 to 28. On flowers of Gaillardia 
pulchella Foug., and Lippia lanceolata Michx. Mainly Neotropical and 
Lower Sonoran, but even extending into the Upper Sonoran exceptional- 
ly. (See case of occurrence in Rio Bonito Valley, belonging to the Pecos 
river system. This valley is in the edge of the Sacramento Mountains, 
at an elevation of 6400 feet.) 
11. Eristalis vinetorum Fab. — June 1 to July 3. On flowers of Ver- 
besina cncelioides B. & II., and Gaillardia pulchella Foug. Neotropical 
but ranging into the Lower Austral. 
12. Zodion aTbonotatum Towns, n. sp. — June 24 to July 3. On flow- 
ers of Lippia lanceolata Michx. Nearly allied to Z. splendens J aenn. of 
the Upper Sonoran. 
M3. Ocyptera euchenor Walk. — June 22 to 24. On flowers of Lippia 
lanceolata Michx. This species extends from the Carolinian to the Neo- 
tropical. It enters the Appalachian in the north, as I have recorded it 
from Minnesota, while it is also known from Massachusetts and Quebec. 
