84 THE CANADIAN ENTOMOLOGIST. 



The next subfamily, the Cerambycinaj, is of great extent, and in 

 consequence more difficulty is encountered in arranging the genera. In 

 the use of the table considerable care must be exercised by those who are 

 unfamiliar with the structure of the Longhorns. This is especially true of 

 the first character involved, i.e., the enveloping of the base of the antennae 

 by the eyes. In order to obtain a proper appreciation of this structure, 

 the antennse should be extended forward from the head : in this position 

 it will be seen that in those genera where the '* base of the antennae is 

 partially enveloped by the eyes " a line passing from the anterior or inner 

 border of the upper lobe of the eye to a corresponding point on the lower 

 lobe will pass through the antennal socket, whereas in the other genera 

 this line would run behind the socket. Of course none of the genera in 

 which the eyes are entire (/. c, not emarginate) will belong to the former 

 category, though those with emarginate eyes may belong to either. Com- 

 parisons of a few specimens ought to make this clear.* The remaining 

 characters may be easily verified by careful examination of a few species 

 the positions of which are already known to the student, and with these 

 as a point of departure he should meet with no greater difficulty than is 

 always to be expected in dealing with a group of large size, wherein col- 

 our and sculpture are inconstant and secondary sexual characters well 

 marked. The following table is submitted for generic discrimination ; a 

 short account of the method of using may be useful to some. Suppose 

 on taking up our insect, which we have previously ascertained to belong 

 to this sub-family, we examine the position of the base of the antennae 

 with regard to the eyes, since this is the first point of departure : ascer- 

 taining the antennal bases to be partly enveloped, we find ourselves 

 referred to the number 12 at the end of the line. We now run down 

 along the numbers at the beginning of the lines until we reach 12, which 

 shows us where to recommence our analysis, with a scrutiny of the second 

 antennal joint. Suppose we find this joint large, we are referred to the 

 number 36, under which (on searching out its position at the beginning of 

 a line) we are again confronted with a query, this time as to the relative 

 proportion of the second joint to the fourth ; if these two joints are about 



*Cases will, however, arise in which this point is in doubt. In such an event the 

 choice will rest between the Callidioides and the Cerambycoides. The former have the 

 second antennal joint larger (as a rule) than the latter, but I can find no hard and fast 

 distinction which will serve the beginner as a sure test. A certain number of properly 

 named specimens serving as a guide to tribal and generic facies is almost indispensable 

 here. It should be stated that the table is based on the characters developed in the 

 " Classification," but is intended to apply only to the Canadian fauna, 



