558 C. R. OSTEN SACKEN'S PRODROME 



and the root of the wings. Abdomen rufous ; second segment with an ill-defined, black, 

 cloud-like spot anteriorly, in the middle ; similar black shades of variable extent on the 

 following segments, so that on segments four, five and six, the anterior two thirds of the 

 segment are often blackish brown, leaving a rufous posterior border, which is broader lat- 

 erally ; the black regions are clothed with short black pile, the rufous ones with reddish 

 golden pile ; a faint reddish yellow triangle is usually visible in the middle of the hind 

 margin of the second segment ; it is still less distinct, often obsolete, on the following seg- 

 ments. Venter uniformly yellowish rufous ; the last segment with some black pile. Legs 

 black, basal part of the tibiae red, to a greater or lesser extent ; hind tibite with a fringe of 

 hairs, which is red above, black below. Wings tinged with brown, which is moi-e saturate 

 along the veins ; a distinct brown cloud on the bifurcation of the third vein ; paler clouds 

 on the crossveins ; first posterior cell closed. 



Hah. Kentucky (G. Dimmock) ; Georgia (H. K. Morrison). Nineteen females. 



The reasons which induce me to believe that this is the true T. abdominalis of Fabricius 

 have been stated on p. 434. 



T. exul. First posterior cell open, although strongly coarctate at the end ; front (?) broad, frontal cal- 

 losity of the corresponding breadth. Length (?) 18-22 mm.; {$ ) about 20 mm. 



Female. Very much resembles T. abdominalis in the coloring of head, thorax and 

 wings ; the palpi are dark reddish brown, densely beset with minute black hairs. The 

 abdomen is much less rufous in coloring and has, on segments two to five, well marked, 

 elongated yellowish white triangles, which do not quite reach the anterior margin of the 

 segment. Other differences, which I perceive in most specimens, consist in the color of the 

 frmge of hairs on the hind tibiae, which is altogether black here, and not red in its upper 

 portion ; and in the antennae, the third joint of which is a little narrower. 



Male. Head subhemispherical, with a well marked dividing line between the large and 

 small facets of the eye ; general coloring more brownish, especially the abdomen ; each 

 abdominal triangle has a dark spot at its apex ; the lateral margins, anteriorly, are also 

 marked with black. 



Hab. District of Columbia, Maryland, Pennsylvania, New Jersey. Twenty females and 

 three males. 



I possess a specimen of T. abdominalis in which the first posterior cell is very distinctly 

 open ; nevertheless the narrowness of the front and other charactei's help to distinguish 

 this species. In the same way specimens of T. exiil may perhaps occur with the first pos- 

 terior cell adventitiously closed. 



The synonyms from Palisot and Wiedemann most probably belong to T. exul. On page 

 436, line 3 from bottom, and on page 437, line 18 from top, read T. exul for T. abdomina- 

 lis. The analytical table, on p. 428, will have to be read thus : 



,„ ( First posterior cell closed ; front remarkably narrow .6. abdominalis Fab. 



(. First posterior cell open 10a. 



{Head of the male subhemispherical ; in the female the abdominal triangles are of moderate 

 size 6rt exul n. sp. 

 Head of the male but little different from that of the female ; abdominal triangles large and 

 broad V tectiis n. sp. 



