LYMEXYLIDAE. 231 



Fam. XLIX.— LYMEXYLIDAE. 



Mentum small, quadrate, corneous; ligula coriaceous, 

 small; palpi 3-jointed. 



MaxilUe exposed at base, with two small ciliatc lobes; 

 palpi 4-jointed, stoat, in the male very large, flabellate, ex- 

 cept in Micromalthus. 



Antennai inserted at the sides of the head, 11-jointed, 

 serrate. 



Head deflexcd, narrowed behind; mandibles moderate, 

 labrum and cljqieus distinct. 



Prothorax with the lateral margin well defined, except in 

 Micromalthus, side pieces not separate; prosternura short; 

 coxal cavities round, confluent in our genera, open behind. 



Mesosternum small, flat, side pieces large, attaining widely 

 the coXcTe. • 



Metastcrnum long, with narrow side pieces; epimera not 

 visible. 



Elytra nearly as long as the abdomen in our genera, much 

 abbreviated in Atractocerus. 



Abdomen with five free ventral segments in Lymexylon, 

 with six in Ilylocoetus and Micromalthus. 



Anterior coxa3 conical, large, prominent, contiguous in 

 our genera, distant in Atractocerus ; middle coxee also 

 large, conical, contiguous ; posterior coxas transverse, coni- 

 cal, prominent internally, contiguous. 



Legs slender, moderately long; tibiee with small terminal 

 spurs; tarsi 5-jointed, filiform; claws simple. 



Tliis family contains bnt four jrt'nera, of wirdi one, Atracto- 

 cerus, has not yet occin-rcd in our fauna, but may be expected in 

 Arizona or Texas, as T Imve already seen specimens from Chi- 

 huahua. A species of Ijymexylon is very destructive to sliip 

 timber in northern Europe, but no dnnjrer is to be apprehoiided 

 from our species, which is very rare. The irenns TTylocoetus is 

 remarkable for having a small deep b'ne at the middle of the vertex. 



AMoTripn with six ventral sppnipnts, elytra entire. Hylocoetu-s. 



Alirlnmen witli five ventral sesrments, elytra entir(>. Lvmexvlon. 



Elytra slinrtt>r than tlie alxlonicn : size very small. Micromalthus. 



One species of each genu.s occurs in the Atlantic region. 



