Ko. 2323. LARVAE OF THE CLERIDAE—BOVJNG AND CHAMPLAIN. 601 



curved, not contracted apex, while the Erwclerus specie's in question 

 have differently built cerci. In general it may be said that in the 

 family Cleridae the form and the position of the cerci can not be 

 used as a character of generic, only of subgeneric or specific value. 

 This is particularly apparent in the present genus, as the different 

 species of Enoclerus^ vphich unquestionably belong here, are to be 

 separated into two subgenera just according to two different types of 

 cerci. Instead of making Thctnasimus a special genus it will logi- 

 cally be placed as a subgenus of genus 2, equivalent to the two other 

 subgenera. 

 These three Subgenera are characterized as follows: 



Cerci cylindrical, with recurved, not contracted 



apex Subgenus 2a (Thandslmus). 



Cerci conical with long gradually attenuated and 

 slightly recurved apex, or subcylindrical, dis- 

 tally slightly swollen and slightly contracted 



apex Subgenus 2& (Enoclerns Ich- 



neumoneus, E. quadrisigna- 

 tus, E. quadrigiittattis, E. 

 humeralis). 

 Cerci subcylindrical, distally swollen, with short 



abruptly contracted, dentiform apex Subgenus 2c. (Enoclerus ros- 



marus, E. muttkotvskii) . 



Subgenus 2a. 



(Figs. 79, SO.) 

 THANASIMUS DUBIUS Fabricins. 



(Figs. 44-46, 79, 80, 103, 111. 122.) 

 No. 1795, U. S. N. M., Marquette, L. S. Mature. Species reared ; imago preserved. 

 Total length, 13 mm.; extreme width, about 2^ mm.; anterior 

 width of prothorax more than two-thirds of the extreme width. 

 Corneous parts shiny, Roman sepia ; delicately chitinous parts shiny, 

 brown ocher; membranous parts purplish, ventrally paler. Setae 

 rather delicate, comparatively long and numerous. Frons with two 

 low and flat, cushionlike longitudinal elevations, one behind the 

 otlier on each side of head, and a shallow groove behind angulus 

 frontalis. Mandible robust; from apex to attachment of retractor 

 tendon five-sevenths the length of frons; length to width as 8^:6; 

 apex right above inner angle of mandibular base ; retinaculum at the 

 middle of inner margin; margin between retinaculum and end of 

 apex entire; two mandibular setae. Meso- and metathoracic dorsal 

 plates well developed, the metathoracic being a trifle smaller. Basal 

 plate of cerci about same length as frons, a trifle wider than long. 

 Cerci cylindrical, somewhat converging, about two-thirds the length 

 of basal plate; distance between the outersides of cerci where these 



