Vol. XXV] ENTOMOLOGICAL NEWS 9 



Fig. 3. Piece of cast larval skin of Hornia gigantea. 



Fig. 4. Pupa of Hornia gigantea. 



Fig. 5. $ type of Hornia gigantea. 



Fig. 6. $ type of Hornia gigantea. 



Fig. 7. Triungulin found on leg of the bee, Anthophora occidentals. 



Fig. 8. Head of $ cotype of Hornia gigantea. 



Fig. 9. Maxillary palpus of $ type of Hornia gigantea. 



Fig. IO. Fore tarsal claw of $ type of Hornia gigantea. 



Fig. ii. Antenna of $ Hornia gigantea. 



Plate II. All figures except Fig. 15 reduced. 



Fig. 12. Bird's eye view of a colony of the larvae of Amblychila 

 cylindriformis, on the sloping bank of White Woman 

 Creek, Greeley County, Kansas, August, 1910. The pen- 

 knife placed in the figure for comparison, is y/& inches 

 long. The shaded holes are closed. 



Fig. 13. Vertical view of a colony of the larvae of Amblychila cylin- 

 driformis, Wallace County, Kansas, August, 1910. 



Fig. 14. Vertical section through a tunnel of the larva of Amblychila 

 cylindriformis, Wallace County, Kansas, August, 1910. 



Fig. 15. Dorsal and lateral view of a mud nest of Heterocerus sp. 



Fig. 16. Vertical section through a tunnel of the larva of Amblychila 

 cylindriformis, Morton County, Kansas, August, 1911. 

 Photo by Love joy. 



The Species-status and the Species-concept. 



By CHARLES H. T. TOWNSEND, Lima, Peru. 



The question as to what constitutes a species is as old as the 

 science of biology. Nevertheless it is not yet satisfactorily 

 answered. In the case of certain groups of plants and animals 

 the answer is simple. These groups belong to old stocks that 

 have long since passed through their period of evolutional 

 activity, are- no longer undergoing extensive variation and 

 specialization, and have lost at least in great part the transi- 

 tional forms that arose during the process of their evolution. 

 But when we attempt to define a species in younger groups 

 which are still undergoing extensive evolution, or have but 

 recently reached the climax of multiform development, the 

 answer is not simple. Examples of such groups are furnished 

 by the Muscoidea among insects and by the Compositae among 



