NEW BARK BEETLES BLACKMAN 343 



KEY TO THE GENERA OF MICRACINAE 



1. Antennal club with distinct sutures on outer face ; antennal scape 



clavate or flattened, widened and subtriangular, funicle with 



6 segments 2 



Antennal club without distinct sutures on outer face; antennal 

 scape clavate or slightly flattened, funicle typically with 6 seg- 

 ments but variously modified and occasionally with fewer 7 



2. Posterior end of elytra drawn out to form an acuminate sutural 



apex 3 



Posterior end of elytra conjointly rounded 5 



3. Antennal scape club shaped, with a few short or moderate hairs, 



club with first suture broadly curved ; eyes short oval, widely 

 separated above and beneath ; fore tibia slightly wider distally, 

 with both edges sinuate, distal end with 2-5 submarginal 



teeth Hylocurus Eichhoff 



Antennal scape flattened, subtriangular, with numerous long hairs, 

 club with first suture angulate or narrowly curved ; eyes large, 

 elongate, more coarsely granulate, contiguous, narrowly or mod- 

 erately separated beneath ; fore tibia with outer margin nearly 

 straight 4 



4. Eyes moderately separated beneath, their inner margins entire ; 



fore tibia with 5 teeth, all on distal submargin, terminal mucro 



broad Micracis LeConte 



Eyes contiguous or narrowly separated beneath, their inner out- 

 lines emarginate ; fore tibia with 5 teeth, at least one of which 

 is on outer submargin, terminal mucro slender Micracisella Blackman 



5. Antenna with scape crudely club shaped, not twisted, with long 



hairs, club strongly flattened, sutures marked by setal rows of 

 short hairs; fore tibia similar to that of Micracis, with sides 

 nearly straight and subparallel, with mucro wide and shorter ; 



elytral declivity not sulcate G 



Antennal scape twisted clavate with fewer long hairs, club mod- 



. erately flattened, sutures marked by rows of long hairs and by 



strong annalations ; fore tibia somewhat similar to that of 



Hylocurus, wider distally with sides sinuate, mucro long, rather 



slender ; elytral declivity sulcate Stenoclyptus, new genus 



6. Pronotum longer than wide, widest near middle, with sides weakly 



arcuate, subparallel, summit not high, posterior area horizontal ; 

 fore tibia wide, with distal end squarely or obliquely truncate, 



terminal mucro entire Thysanoes LeConte 



Pronotum wider than long, widest near base, its outline subsemi- 

 circular or subtriangular, summit high, posterior area sloping ; 

 fore tibia narrower, distal end obliquely truncate, terminal 

 mucro sometimes bifurcate Pseudothysanoes Blackman 



7. Antennae of male and female similar, funicle slightly longer than 



the short ovate club , Cryptocleptes Blackman 



Antennae of male of the normal micracine type ; that of female 

 with funicle more than twice as long as club or scape, club 

 elongate-securiform in female Chalcohyus, new genus 



