DESCRIPTION OF A NEW DRAGON FLY FROM LOWER 

 SIAM BELONGING TO THE GENUS UROTHEMIS 



By F. F. Laidlaw 



Of Ufculme, England 



The new species described below belongs to the Libelhilid sub- 

 fa iniiy LibelhiHnae. The material from which the species is described 

 was collected by Di'. W. L. Abbott and forwarded to me for study 

 by the United States National Museum. Since a detailed report on 

 the oriental material of the subfamily Libellulinae can not be com- 

 pleted for some time it seems desirable to publish the description of 

 tills interesting new form in advance of the complete report. 



rROTHEMUS ABBOTTI, new spefies 



Material. — One male (holotype). One female (allotype). Two 

 males (paratypes). 



Dflto.— Trong, Lower Siam. Dr. W. L. Abbott. (Coll. U. S. Nat. 

 Mus.) (Specimens to ho ret,i:irned to U. S. National Museum.) 



Venation. 



I. Ante and post nodal cross nei ves. 



7-8 ! 8-7 7-8 I 8-7 „ 



, — holotype. ^ i— — ^.allotype. 



7-6 I 6-7 '^ 7-6 I 6-7 



7-8 i 8-7 7-9 I 8-7 



r~_- hr— ;:Pai"^it.ype a. -—— — — -paratype h. 



7-0 ; 5— / 8 — o I o — 7 



II. Cell rows of discoicuil field of fore wing. 



Between the triangle and the beginning of Mspl there lie seven or 

 eight rows of cells in this field. After the first cell the row is gener- 

 ally three cells deep, but in the specimen indicated as paratype h the 

 row is only two cells deep, on the right side for the first six cells, on 

 the left side for the second to the sixth cell. 



Mspl incloses invariably a single row of cells, about six in number. 



III. Rows of cells between R^ and Bspl. 



Invariably two cells deep at its center, on both fore and hind wing, 

 for a distance of one, two, or even three cells. The supplement in- 

 closes a row of nine or ten cells. It is two cells deep for a length of — 

 1 ceil j 2 cells , , ^ 3 cells I 3 cells „ ^ 



3 ceUs I 3 cells 1 cell i 1 cell 



3-^dir T^lfs P'-^^^^yP^ «■ r^l hr^ paratype b. 



No. 2666.— Proceedings U S. Natjoival Museum, Vol. 70, Art. 17 



21997—27 1 



