1915.] NATURAL SCIENCES OF PHILADELPHIA. 503 



base, the distal portion spatulate, flattened; inner pleural appendage 

 with the lower or caudal arm flattened, expanded at the apex, pale 

 in color and directed almost dorsad; the surface of the arm is rough- 

 ened, hairy; the upper or cephalic arm is flattened, chitinized. 

 Ninth sternite with the caudal margin very gently concave medially, 

 the caudo-lateral angles produced into rounded knobs which are 

 produced into lobes on the ventral inner face, the lobes covered 

 with long yellowish hairs; the ventral surface of the sternite rather 

 extensive with a deep and broad median groove. Eighth sternite 

 (see Plate XVII, fig. 30) small, the caudal margin gently concave 

 medially, on each side with tufts of long yellow hairs which are 

 decussate. 



Habitat. — Eastern United States. 



Holotype, cf , District of Columbia. 



Allotype, 9 , Plummer's Island, Md., April 25, 1915 (McAtee). 



Paratype No. 1, cf , topotypic; No. 2, d^ , Plummer's Island, Md., 

 April 25, 1915 (McAtee); No. 3, 2 c^'s, with the last on April 28, 

 1915; No. 5, cf 9 , Maryland, near Plummer's Island, April 28, 

 1915; No. 7, cf 9 , Virginia, near Plummer's Island, April 28, 1915. 



The type, is in the collection of the Museum of Comparative 

 Zoology; paratypes 1, 2, 5 and 7 in the collection of the author; 

 the remaining paratypes and the allotype in the collection of the 

 Biological Survey. The material on which the species is partly 

 based is from the Loew-Osten Sacken collection and was probably 

 taken in the vicinity of Washington by Osten Sacken. 



T. dietziana is respectfullj- dedicated to Dr. William G. Dietz. 



The species is closely allied to T. australis Doane and may be 

 separated from that species by means of the following key: 



1. Antennae short, the flagellar segments deeply constricted beyond 

 the basal enlargement; six bro^vn stripes on the mesonotal 

 prsescutum; male hypopygium with the ninth tergite almost 

 straight across the caudal margin with a deep and narrow 

 impressed median furrow; ninth pleurite distinctly complete; 

 lobes of the caudo-lateral angles of the ninth sternite, pendu- 

 lous, directed ventrad, the apex clothed Avith short golden 

 hairs; eighth sternite with four conspicuous lobes, the outer 

 pair very broad and flattened, their apex oblique; the inner 

 pair of lobes are the divaricate ends of a median process on the 

 caudal margin of the sternite, their apices clothed Avith a 

 dense brush of golden yellow hair australis Doane.^ 



^australis Doane ; Journal of the New York Entomological Society, vol. 9, 

 :No.3, pp. 104, 105; 1901. 



