58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



The testes consist of two oval structures which are closely connected 

 medially. The vasa deferentia is Y shaped. The mucous glands are 

 wide and stout and about as long as the testi. The seminal vesicle is 

 represented by a subsphericle structure to the upper side of which the 

 glands are joined. The ductus ejaculatorius is comparatively short, 

 stout, and as long as the testi. In Nuesslin's key to the larger groups 

 of Scolytidae, based on the male reproductive organs except the penis, 

 GnafhotricJiits falls near to the Enwpor'mae. 



Penis. — In order to consider the penis of Gnathotrichus, it is first 

 necessary to discuss in a general way the Scolytid penis. 



Lindeman, who was the first investigator of the Scolytid penis, dis- 

 tinguished two main groups of elements, the primary and the acces- 

 sory. He states that the primary elements, which comprise the body 

 (Koerper), the fork (Gabel) and the stalk (Stengel), are constant 

 throughout the family Scolytidae, while the accessory elements, which 

 form together the so-called Aufsatz, vary considerably in the dif- 

 ferent genera as well as from species to species in one genus. Ver- 

 hoeff, the second to deal with the subject, did not agree with this 

 classification, while Nuesslin supported Lindeman's opinion. The 

 last of the more important investigators of the Scolytid penis, Dr. 

 Fuchs, constructed a new system for such a classification, without 

 consideration of the phylogeny, and distinguished covers (Huellen), 

 inclosed parts and parts external to the covers. The author cannot 

 agree with Lindeman and Nuesslin that the primary elements always 

 included in the Scolytid penis consist of the fork (parameren Ver- 

 hoefif) and the stalk (spiculum ventrale (Fuchs)). Already Fuchs 

 has shown how far the reduction of the parameren and the spiculum 

 ventrale in the European Hylcsinidac has gone and the author is con- 

 vinced that more intensive investigations of this subject will bring 

 up many new facts. Without doubt more than three-quarters of the 

 genera and ninety per cent of the species of the Scolytidae have not 

 been studied at all or not thoroughly enough. For example, it was 

 found in the present study that the spiculum ventrale is absent in 

 Gnathotrichus, and it will not be long until genera are found in which 

 the complete loss of the parameren occurs. If it is desirable to dis- 

 tinguish between primary and accessory elements, the author would 

 prefer that the primary elements be considered the body only, the 

 accessory elements all the parts outside of it. For further studies of 

 this subject, the author will adopt Dr. Fuchs' classification and nomen- 

 clature until a time when sufficient new material is available to fur- 

 nish new conclusions. 



