940 CHARLES PAUL ALEXANDER 
b. The umbrosa subgroup.— Large species; the eighth sternite provided with conspicuous 
lateral lobes, and the caudal area between with two ‘chitinized points. 
T. umbrosa Loew 
T. flavoumbrosa Alex. 
ce. The australis subgroup.— Medium-sized species; the lateral lobes of the eighth sternite 
(T. australis) tending to disappear (7. dietziana) and pass into the fourth subgroup. 
T. australis Doane 
T. dietziana Alex. 
d. The submaculata subgroup.— A great assemblage of forms, including the majority of 
the subunicolores. Wing practically unicolorous (except in 7’. huron) but the obliterative 
streak well marked; ninth tergite variously notched medially; eighth sternite provided 
with tufts of short to long hairs, in the specialized forms (7. tuscarora) passing into a 
single powerful bristle on either side. 
. mainensis Alex. 
. mingwe Alex. 
. georgiana Alex. 
. monticola Alex. 
. translucida Doane 
. cincticornis Doane 
. penicillata Alex. 
. triton Alex. 
. submaculata Loew 
. tuscarora Alex. 
huron Alex. 
besselst group.— A small group of high arctic species; coloration blue-gray; head, 
thorax, and coxae with abundant long white hair; valves of the ovipositor suddenly narrowed, 
weak. 
T. besselsi O. S. 
T. piliceps Alex. 
6. The aperta group.— A reduced species, with the venation in process of atrophy, the 
medial cross-vein lacking. 
T. aperta Alex. 
7. The apicalis group.— An isolated species that has probably come from the valida group; 
wing broadly tipped with brown; ninth tergite deeply notched medially. This species is 
possibly closer to T. mainensis than this grouping would indicate. 
T. apicalis Loew 
8. The hermannia group.— Wings sparsely blotched with darker; ninth tergite with 
a prominent, compressed, median lobe; antennae of the male elongate; not dimorphic. 
T. hermannia Alex. 
9. The annulicornis group.— Dimorphic, the males light-colored, the females dark brown, 
the wings practically unicolorous; male antennae elongate to very elongate (7. taughannock); 
ninth tergite with a conspicuous median lobe and more or less prominent lateral lobes. 
T. annulicornis Say 
T. taughannock Alex. 
10. The fuliginosa group.— Dimorphic, the males light-colored (7. speciosa), the females 
very dark brown (7. fuliginosa) with white markings; ninth tergite asymmetrical, the 
right pleurite produced caudad in a prominent two-cleft arm; ninth tergite deeply notched 
medially. 
T. fuliginosa (Say) 
11. The trivittata group.— Wings conspicuously cross-banded, an uninterrupted white 
band beyond the cord; ninth tergite notched, with a small tooth at the base of the 
notch. 
T. trivittata Say 
T. angulata Loew 
T. entomophthorae Alex. 
SP ARARRA RAR AAAR 
on 
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