PTINIDAE. 203 



Tylistus, are nearly globular. The antennae are distant at base 

 and inserted immediately in front of the eyes ; they are either 

 simply serrate, or have the three outer joints longer; rarely (male 

 of Ptilinus) they are flabellate. The hind thighs in repose are 

 received by the hind coxae, which are deeply sulcate behind for 

 that purpose, and form a plate, which is not dilated inwards. The 

 trochanters are short ; the legs are retractile, the tibiae have obso- 

 lete spurs, and the first joint of the tarsi is not shorter than the 

 second. The lateral margin of the pronotum is distinct in all of 

 our genera. 



Two tribes are represented in our fauna : — 



Eyes almost in contact with the prothorax. Anobiini. 



Eyes distant from the prothorax. Ptiliniki. 



Tribe I— ANOBIIrVI. 



The form is less regularly cylindrical than in the next tribe ; 

 the head is usually very retractile and deflexed, so as to be not 

 visible from above, in a state of repose, and the eyes are in con- 

 tact with the anterior margin of the thorax. 



Three groups may be formed, thus : — 



Prothorax much excavated beneath, for the protection of the mouth ; 



Mandibles dilated at base. Xylettni. 



Mandibles not dilated at base. Anobia. 



Prothorax not excavated beneath. Dryophili. 



Group I.— Xyletini. 



The insects of this group are more robust than those of the 

 other groups, and the contractile power here attains its highest 

 perfection. The genera form two sub-groups, according to the 

 form of the antennae. The large and stout mandibles are dilated 

 at the base ; the first joint of the antennae is frequently large ; the 

 head is received closely on the breast, and the legs are tightly 

 contracted in a state of repose. An oblique line, sometimes 

 elevated so as to form a margin, runs from the eyes to the base 

 of the labrum ; the plates of the hind coxae are moderately wide. 



Our genera may be separated thus : — 



Metastemum advanced between the middle coxse ; 

 Three outer joints of antenna? very large; 

 Metastemum emarginate, eyes entire. ErrACTUS. 



Metasternum truncate, eyes divided or emarginate. Tylistus. 



