COLEOPTERA. 515 



MoNOTOMA, 



Is distinguished from the first by the solid and globuliform club 

 the tenth joint of the antennae. 



The body is elongated, depressed, and frequently forms a paral- 

 lelopiped; the anterior part of t!je head is narrowed, and projects 

 somewhat in the manner of a triangular and obtuse snout. The 

 palpi are very small, and, as well as the mandibles, not salient. 



In some, the head is not separated from the thorax by a strangu- 

 lation or sort of neck, and can be received into it. 



Synchita, Hellw. Dej. Lyctus, Elophorus, Fab. 



Where the anterior extremity of the head is transverse and with- 

 out any prolongation, where the two first joints of the antennae are 

 almost identical, and where the thorax, much wider than it is long, 

 is separated from the base of the elytra by an evident interval(l). 



Cerylon, Lat. Synchita, Hellw. Lyctus, Fab. 



Where the anterior extremity of the head projects in the manner 

 of an obtuse triangle; the first joint of the antennas is much larger 

 than the second; the thorax is applied posteriorly to the base of the 

 elytra, is wider than it is long, or almost isometrical, and without 

 any recurva'ture of the margin. The body is almost oval or nearly 

 forms a parallelopiped, and the elytra are truncated posteriorly and 

 cover the whole top of the abdomen(2). 



Rhyzophagus, Herbst. Gyll. Lyctus, Fab. 



Resembling the preceding in the head, the relative dimensions of 

 the first joints of the antennae, and the junction of the thorax with 

 the abdomen; but the body is narrow and elongated, the thorax 

 wider than long, with a recurved margin; the elytra are truncated 

 posteriorly. Some authors have asserted, that by their tarsi, they 

 are Heteromerous I rather think they prove them to be Pentamer- 

 ous(3). 



The others, 



(1) Cerylon terebrans, Lat.; C.juglandis, Gyll.; Lydus juglandis, Fab.; Elopho- 

 rus humeralis, Ejusd. 



(2) Cerylon histeroldes, Lat., Gyllenhall. 



(3) See Gyll., Insect. Suec, I, iii, p. 419. 



