1873.] O^ [Crotch. 



PARXID.E. 



Anterior coxae transverse, cavities open, trochanter distinct. 



Posterior coxa? dilated into a plate, contiguous. 



Ventral segments 5, 1-3 connate. 



Tarsi 5-jointed. 



Antennae short irregular, as in the Gyrinidce, to which this family is 

 evidently allied, though differing remarkably in the form of the coxa;. 

 Leconte's two sub-families entirely destroy the homogeneity of this 

 family and are made into separate families. 



ELMID.E. 



Anterior coxae small, rounded, without trochanter, cavities open. 



Posterior coxae transverse, distant. 



Ventral segments 5, 1-3 connate. 



Tarsi 5-joined, 5th elongate. 



Allied to Parnidm by mode of life, and more or less by the appearance 

 of the larvae ; but remarkably distinct structurally. Antennae shoit. 

 hardly sub-clavate. The tarsal structure is very like Hydrochus but the 

 broadly distant coxae entirely remove it. 



HETEROCER1D.E. 



Anterior coxae transverse, cavities open. 

 Posterior coxae sub-contiguous. 

 Ventral segments 5, 1-3 connate. 

 Tarsi 4-jointed. 



Antennae 10-11-jointed short, irregular. Evidently allied to Parnid '. 

 but with a very characteristic facies. 



Histerid.e. 



Anterior coxae transverse, cavities open. 



Posterior coxae distant, sub-quadrate, not reaching the margins. 



Ventral segments 5, 1st very large. 



Tarsi 5-jointed (Acritus 5, 5, 4), legs retractile. 



Differs from the other families by the geniculate antennae, with a com- 

 pact rounded club ; elytra truncate, 2 dorsal segments uncovered, cor- 

 neous. Murmidius, placed here by Dr. Leconte, seems to me certainly 

 an aberrant form of Colydiidce. 



The two families of Lamellicornes are easily distinguished. The Serri- 

 corn series also is well arranged by Leconte. The Tetramera include 

 only 3 families, Cerambycidie, Bruehidce, Clirysomelidae, and their limits 

 are hard to define. The Heteromera have been divided by Leconte into 

 convenient families; possibly Lagria and Alleeula (Gistelai should go in 

 Tenebrionid<:e and certainly Nilio should go with Pythidm, bearing as Dr. 

 Horn has suggested to me, the same relation to it as Thy mains does to 

 Trogositidm. The Rhynehophorus families are still doubtful, probably 

 there are only three, Anthribidce, Cureulionidm and Scolytidm. 



