1878. ] ; 591 [Horn, 
The following genera have been placed with the Colydii- 
de, and, as mention has been already made of their exclusion, 
it is proper that they should be appended to the main essay. 
MURMIDIID®. 
The differences between this family and the Colydiide have been pretty 
fully dwelt upon by Duval in the Genera of Coleoptera of Europe, so that 
comparatively little may be added. 
The parts of the mouth are very difficult to examine, but those of Mycho 
cerus seem not remarkably different from those of Cerylon, especially in the 
form of the palpi. The head is completely retractile in Murmidius and the 
parts of the mouth are concealed beneath by a distinct prosternal lobe, while 
in Mychocerus the head is less retracted and the lobe very short. The an- 
tenn are rather frontal in their insertion resembling the Histeride, ten- 
jointed, terminated by a solid club composed evidently of two joints united, 
the basal joint is stout, and the joints of the funicle are suddenly geniculate, 
the club being received either in a cavity at the anterior angle of the thorax, 
open above (Murmidius), or in a cavity in the front of the anterior angle 
not opening above (Mychocerus). The anterior coxe are smail and round, 
their cavities open behind, but completed by excavations in the anterior 
border of the mesosternum, which is closely applied to the posterior edge 
of the prothorax. The middle coxe are small and as distant as the anterior. 
The posterior cox are small, very slightly oval and almost completely sur- 
rounded by the metasternum in front and the first abdominal segment be- 
hind. The prosternum is broad, flat and bistriate. The metasternal side 
pieces are concealed by the epipleure in Murmidius but are quite distinct in 
Mychocerus. The legs are retractile and received in excavations at the 
sides of their respective sterna, the cavities for the posterior being partly 
in the first abdominal segment. The abdomen is as in Cerylon, the first 
segment being long the others short and each slightly shorter than the pre- 
ceding. The tarsi are four-jointed, the last joint being as long as the others 
together. 
The essential difference between this family and the Coly- 
diidve are found in the presence of the antennal cavities and 
their position, the presence of a prosternal lobe more or less 
marked, the structure of the anterior coxal articulation, the 
legs retractile and finally the structure of the posterior coxal 
cavities. In the latter character there is some resemblance 
to Discoloma. 
The resemblances to the Histeridze entirely escape me ex- 
cept in the retractility of the legs, while the structure of 
the anterior coxve is so widely different in the two families 
as to completely outweigh the more trifling similarities. 
