18 GEO. H. HORN, M. D. 



PLATE II. 



Right half of abrlomen, showing the position of spiracles in Pleocoma. 



Diagram in transverse section showing the relation of spiracle to adja- 

 cejit parts. 



Anterior and posterior tibiie of P. fimhriufa. 



Lateral view of head of P. hirticoUis, the mouth parts removed. 



Front view of clypeiis and labrum. 



Head beneath, showing the relation of parts, the maxillse are not so 

 plainly visible in nature. 



Mandibles as seen from beneath hi situ. 



Right mandible as seen from side. 



Right mandible (more enlarged) as seen from the upper side. 

 Fig. 10. Left maxilla, the side adjacent to mentoni. 

 Fig. 11. same the side adjacent to mandible. 



Fig. 12. Right maxilla « lower side, b U])per side of Bradycinefits femujineus. 

 Fig. 13. Mentum and ligula of same. 

 Fig. 14. Mandible of same. 



Fig. 15. Maxilla of Aphodius errat'icHs (after Duval). 

 Fig. 16. Mentum and ligula of same (after Duval). 



Fig. 17. Form of maxilla of larva of Pleocoma from a sketch of the cast skin. 

 Fig. 18. Mentum and ligula of same. 



Descriptions of llio larvjv of dilyptus, Platypsylla 

 and Folyphylia. 



BY GEORGE H. HORN, M.D. 



The larvJB of Coleoptera will doubtless yield facts of taxonoinic 

 value, and may aid in settling disputed relationships among the im- 

 agines. Some attempts have already been made in this direction, 

 notably by Erichson and othei*s among the Scarabseidse, and more 

 recently by Rey in Elaterida^. Borne families have yielded very 

 little, from the fact that the species have almost the same mode of 

 life as Cerambycidse, Buprestidse, and the majority of the Rhyncho- 

 phora. 



At present too little attention seems to be paid to study of this 

 sort, and every student of classification should consider it a duty to 

 describe any authentic larva known to him with such figures of form 

 and detail as may be useful hereafter. 



Recently three larvse have come into my possession, two of which 

 are entirely new, the third merely showing the almost absolute iden- 

 tity of our form with that of European species, and in accordance 

 with the idea above explained the following descriptions are given 

 with figures and details on the accomi)anying plate. 



