Dec. 1897.] Townsend : Diptera from the Tamaulipan Region. 1T1 
DIPTERA FROM THE LOWER RIO GRANDE OR 
TAMAULIPAN REGION OF TEXAS.—I. 
By C. H. Tyler Townsend. 
The present paper is the first of a series to be published on the 
dipterous fauna of the region of the Lower Rio Grande, in Texas and 
Tamaulipas. The material described was collected by the writer, princi¬ 
pally near Brownsville, Texas, while engaged as Field Agent of the 
Division of Entomology, of the U. S. Department of Agriculture. 
The writer has already published, in the Transactions of the Texas 
Academy of Science, i, pp. 71 to 96, a paper on biogeography, which 
includes mention of the Lower Rio Grande district. This district forms 
a part of the Tamaulipan fauna, which may be recognized as extending 
from the Nueces river region in Texas to the central or southern part of 
the Mexican State of Vera Cruz. Several months’ collecting done by the 
writer in the Lower Rio Nautla region of the State of Veracruz, since the 
above paper on biogeography was published, has shown that that local¬ 
ity must come within the limits of the Tamaulipan fauna, as possessing 
many temperate forms of insects. A considerable number of these tem¬ 
perate forms may range as far south as the Coatyocoalcos river, or even 
farther. 
It is pointed out in the above mentioned paper that at best the 
insect fauna of Lower Rio Grande, from an examination of some 500 
species of Coleoptera and Diptera, shows somewhat less than twenty- 
five per cent, of Neotropical forms. Probably the percentage will run 
lower on the examination of a greater mass of material. The district is 
mainly Lower Sonoran ; but there is, beside the Neotropical (.Mexican 
province of the tropical transition zone), a considerable element of 
Austroriparian , and even a few Upper Sonoran forms reach down to it 
from the west, while a maritime Antillean fauna reaches up the Mexican 
coast line and keys to Padre Island. The fauna of this district is there¬ 
fore rich in forms, as particularly evidenced by the Coleoptera so far 
collected, for no less than five great life provinces tend here to meet and 
intermix their constituent elements to a greater or less extent. 
For the determinations of the flowers on which the diptera men¬ 
tioned in this paper were taken, I am indebted to Dr. J. M. Coulter and 
Mr. F. V. Coville. 
SIMULIIDAL 
Simulium tamaulipense, sp. nov. 
9. Length, mm. Near S. meridionale , but smaller and the outer one on 
