148 MUSCID^. 



2. litorea, Fnl. Msc. 94. B (1810); Meig. ; Zett. Fusco-tomen- 

 tosa, subtus cana, capite argenteo, paljm nigris, tborace nigro-subqua- 

 drivittato, alis cinereis, abdomine cinereo, pedibus nigris ; Mas, tarsis 

 intermediis hrevisshnis. Long. 3 ; alar, 5 lin. 



Black, with brown tomentura, hoary beneath and on each side of the 

 thorax. Head silvery in front . Palpi black. Thorax with four slight 

 blackish stripes. Wings grey. Aluke white. Abdomen cinereous. 

 Legs black. Male. Middle tarsi very short. 



Not common. (E. I.) 



Alula indistincta vel nulla. — Div. 2. ACALYPTER^'E, Mcq. 



These are generally distinguished from the Calyptera by their 

 comparatively smaller size, their paler and less compact bodies, 

 their more feeble flight, and by the less developed structure of 

 their autennro. They may be grouped thus : — 

 a. Subcostal and mediastinal veins separate. 

 b. Head transverse. 



c. Pobrachial and anal areolets of moderate length. 



d. Wings almost always unspotted. 1. Helomyzides. 

 d d. Wings very generally spotted. 4. Outalides. 

 c c. Pobrachial and anal areolets very short. 3. Lauxanides. 

 b h. Head round, or elongated. 5. Sepsides. 

 « a. Subcostal and mediastinal veins united. 

 b. Hind metatarsus thick. 2. Borborides. 

 b b. Hind metatarsus slender. 



c. lladial vein ending at not beyond three-fourths of the length of 



the wing. 7. Oscinides. 

 c c. lladial vein ending at much beyond three-fourths of the length 

 of the wing. 

 d. Pobrachial and anal areolets distinct, long. 



e. Discal transverse vein parted by not more than its length 



from the border. 6. Psilides. 

 e e. Discal transverse vein parted by full twice its length from 

 the border. 9. Phytomyzides. 

 d d. Pobrachial and anal areolets indistinct or none. 



<?. Prsebrachial transverse vein distant from the base of the 



wing. 8. Geomyzides. 

 e e. Prajbrachial transverse vein very near the base of the 

 wintr. 10. Hyj)romyzii)1i;s. 



