16 PEOCEEDINGS OP THE NATIONAL MUSEUM vol.81 



Family PLAGIORCHIIDAE Luhe, 1901 

 Subfamily Plagiorchiinae Pratt, 1902 



Genus HAEMATOLOECHUS Looss, 1899 



Synonym : Pneumonoeces Looss, 1902, 



Concerning the status of these two names, Haeinatoloechus Looss 

 and Pneumonoeces Looss, Cort (1915) writes as follows: 



In 1902 on account of Stal's hemipteran genus Haematoloecha established 

 in 1874 Looss (1902:732) changed the generic name Hacnmtoloechus to Pneu- 

 monoeces. He did this influenced by Braun's (1901:55) contention that if 

 family or subfamily names are formed from generic names which differed only 

 in endings, they would be identical. This seems to me to be a logical appli- 

 cation of the rule of priority and I shall accept the later name Pnenmonocccs. 



Cort's opinion in this matter is not illogical, but unfortunately 

 the International Code of Zoological Nomenclature specifically states 

 that a generic name is not to be considered preoccupied when it differs 

 only in ending from a genus already published. As examples, the 

 genera Picus ancZ Pica are cited. Therefore, the earlier name Haema- 

 toloechus must be used. Since this paper was first submitted for 

 publication, the same conclusion has been reached independently by 

 Ingles (1932). It is unfortunate that this change is necessary, since 

 the name Pnemnonoeces has been in common use for nearly 30 years. 



Cort (1915) adequately summarizes our knowledge of this group 

 in North America previous to that date. Since then Irwin (1929) 

 has added one more species, H. farviplexus, and two more are de- 

 scribed below. 



HAEMATOLOECHUS FLOEDAE, new species 



Plate 1, Figube 7 



Specific diagnosis. — Haetnatoloeclius : Flukes of medium size ; the 

 body is elongate, flattened, pointed toward the anterior end but 

 rounded behind. The largest specimen in my possession is 10 mm 

 long; the average, however, are about half that long. The smallest 

 specimen measures 4.4 mm and seems to be fully mature. The width 

 varies from 1.2 to 1.6 mm. The cuticula is smooth and entirely 

 without spines. It is extremely thin, never being more than 4/a in 

 thickness. The large oral sucker measures 3.6 to 4.4 mm in diameter. 

 The ratio between the oral sucker and the pharynx is nearly 

 as 1:2, but the pharynx is often a little smaller ; however, 

 the ratio does not fall below as 2:5. The ratio of the oral sucker 

 to the acetabulum falls very close to as 1 : 3. The acetabulum is 

 only slightly anterior to the middle of the body. In a worm meas- 

 uring 5.4 mm long the acetabulum is 2.4 mm from the anterior end. 



