BIHANG TILL K. SV. VET.-AKAD. IIANDL. BAND 21. AFD. III. NIO 2. 7 



measure 0,o9 to 0,ii mm. in length, aml fre([uently have less 

 obtnse ends than tliose sliewn in Cleve's fignre. 



Kv. 34, S.-K. 33, Gl. 43. — Somewhat rare. 



This species seems to be a variety of P. viridis with 

 slightly undulating margins. 



F. brevicostata Cl. — Finl. pl. I, 5, p. 2b. 



A form, probably belonging to tliis species, occurs in 

 S.-K. 33. It is 0,0 9 mm. in length, 0,oi7 mm. in breadth 

 and lias 8,5 to 9, parallel, very sliort striae in 0,oi mm. Tt 

 seems identical witli A. S. XLIII, 2(3, 27 (with 8 striae in 

 0,01 mm.) I think these forms, considered by Cleve as pos- 

 sibly belonging to P. hemiptera KtJTZ. (se Cl. Finl. p. 25), 

 come nearer to P. brevicostata Cl. 



S.-K. 33. — Rare. 



Var. tennis A. Cl. n. var. — PL I, 4. 



Valve linear, 0,o9 mm. in length, 0,oi2 mm. in breadth; 

 striae 10 in 0,oi mm. Axial area narrower than in the ty- 

 pical specimens. 



Ks. 15. — Rare. 



Var. leptostauron Cl. — Finl. p. 25, A. S. XLIII, 25. 



DiiFers from the above variety only by the striae being 

 interrnpted in the niiddle of the valve. 



Ks. 15, S.-K. 7, Gl. 43. — Somewhat rare. 



P. hemiptera KtJTZ. — A. S. XLIII, 28, 35—40, XLV, 9. — 



Cl. Finl. p. 25. 



Striae slightly radiate, 10 to 11 inO,oi mm. Area about 

 V3 of the breadth of the valve. 



This species comes near to P. brevicostata var. tennis 

 A. Cl. but is distingnished by its ontline, and somewhat more 

 radiate striae. 



Kv. 1, 2G, 32, 34, Nn. 18, 25, Jm. 6, Km. 10, 30, V. 12, 

 S.-K. 7, 33, Gl. 43, Gl. D. 44, Ke. 49. — Pretty freqnent. 



P. isostauron EiiB. — Cl. & Gr. A. D. pl. III, 14. 



It is of ten difficnlt to distingnish this species from P. 

 brevicostata var. leptostauron Cl., which has a little broader 

 area and slightly radiate striae. 



The length of the valve varies from 0,0 5 to 0,ii mm. 



Kv. 1, Nu. 5, Jm. G, 31, S.-K. 22, 33, Gl. D. 45. — Not rare. 



