GENUS iEDES 481 



3. ^. nigricorpus, Theob. Generally resembles the above, but has 



the fork-cells much longer. Thorax dark bronze, unadorned. 

 B. Posterior fork cell as long as the anterior. 



4. ^. Pembaensis, Theob. Thorax adorned with two pale stripes 



in front. 



viii. Abdomen unadorned. 



A. Anterior fork cell longer than the posterior. 



5. ^. Cinereus, Meig. Abdomen nearly black. Thorax dark, with 



a faint, pale median line. 



6. yE. Obscitras, Meig. Generally dusky. Under border of abdo- 



minal segments darker. 



7. ^. Bicf us, Gimmevthsii. Abdomen nearly black. Thorax reddish, 



with median and lateral darker lines. 



8. ^. pertinans, Williston. Abdomen deep brown. Thorax un- 



adorned, brown, and generally dusky. 



9. A^. perturbans, Williston. Abdomen and thorax alike ellow. 



B. Posterior fork-cell as long as the anterior. 



10. ^®. nigei; Theob. Abdomen entirely black. Thorax brown. 

 Pleurae pale. 



1. iEDES FUSCUS, Osten-Sacken. 

 (Bull. U.S. Geol. Surv. p. 191.) 



Abdominal segments steely-black, with creamy basal patches. 

 Ground colour of thorax nearly black, with golden-brown, narrow 

 curved scales. Legs bronzy-black ; the tarsi unhanded. 



Head dusky, with yellow lateral patches, and narrow eye-borders ; 

 palpi very short, black, as also is the proboscis. PleuriB, chestnut-brown 

 with white patches. Venter creamy-yellow. Femora silvery below, and 

 with minute white knee-spot. Tarsal claws of ? , equal and simple; of 

 ^ , on the fore and mid legs unequal, the smaller simple, the larger with 

 extra tooth ; on the hind legs equal, and both toothed. Length. — About 

 4 mm. 



Habitat. — America ; Canada and United States. 



2. ^DES BUTLERI, Theobald (Monog. II, p. 230). 



Abdominal segments intensely black, with white lateral basal 

 spots. Wings with the anterior fork-cell longer than the pos- 

 terior, and quite twice the length of its stem. Ground-colour of 

 thorax black, uniformly clothed with dark bronzy, narrow curved 

 scales. 



5 . — Head black, with lateral patches, a narrow median line, and 

 delicate eye-borders, white ; clypeus and appendages black. Pleurae dark 



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