132 COLEOPTERA OF NORTH AMERICA. 



The clypeus is usually prolonged and margined in front, so that 

 the mouth is inferior, but in Glaphyrini the mandibles and labrum 

 are prominent ; the mandibles are corneous, short, pyramidal ; 

 the mentum large, quadrate, with the ligula usually corneous and 

 connate with the mentum, though sometimes free and membranous, 

 as in the laparosticti ; the clypeal suture is usually distinct, trans- 

 verse ; the antenna? have from seven to ten joints, and the club is 

 always lamellate, sometimes consisting of six or five, but usually 

 of three joints, and is frequently longer in the males; the tarsi 

 are always perfect, 5-jointed, with the claws variable in form, and 

 the bisetose onychium is present in all the tribes except Hoplini. 



The species feed exclusively on living vegetable matter, and it 

 will be seen that the distinctions between it aud the other sub- 

 families are of a negative character ; the posterior spiracles do 

 not diverge strongly, as in the pleurosticti ; the middle coxae are 

 not oblique, as in the laparosticti (except Trogini), nor rounded 

 and separated from the side pieces, as in that tribe. There is also 

 a considerable difference in the adaptation of the last abdominal 

 segments. In Melonthidse the fifth ventral is very frequently con- 

 nate with the penultimate dorsal, and the sixth segment, usually 

 visible, is rendered so merely by its size and firm consistence 

 causing it to be pushed out into view. Even when the fifth ven- 

 tral is not connate with the dorsal segment, they form together a 

 regular ring. 



In the preceding sub-family the sixth ventral segment is nor- 

 mally visible, although sometimes of small size and retracted ; in 

 this case the pygidium or last dorsal segment is covered by the 

 elytra, and in a manner lies upon the fifth ventral. The fifth 

 ventral is never connate with the penultimate dorsal, and does 

 not form with it a regular ring. 



In the first tribe of Melonthidae (Glaphyrini) the sixth ventral 

 is quite visible, and the fifth is not connate with the penultimate 

 dorsal, but still they are adapted together so as to form a regular 

 ring, to which is articulated the protuberance formed by the pygi- 

 dium and sixth ventral, in the same position as in Melolonthidss 

 of other tribes in which the sixth ventral segment is external. 



According to the position of the abdominal spiracles, the tribes 

 of this sub-family divide into two sets. 



