COLEOPTERA SCOLYTID.^. 115 



A. Base of tliorax finely bordered ; prosternum with a 



short process ; size very small ; club of anteniifB 

 divided by three constricting sutures into four 

 joints . . . PiTYoriiTiioiius, Eich. 



B. V>asQ of thorax not bordered. 



a. Club of the antennae with the second joint cresc- 



ent-shaped, and completely embracing the sides 

 of the first joint, which is oval ; scutellum 

 rudimentary ; elytra with reflexed portion dentate 

 in the male, not dentate in the female 



Xyloclbptbs, Ferr. 



b. Club of antenna^ truncate at apex, the basal joint 



being corneous, and the remaining joints lying 

 within it ; mentum broadly cordate, sub-mentum 

 large and concave anteriorly . Dryoc^tes, Eich. 

 //. Elytra excavate at apex, which is horizontal or almost 

 horizontal behind the apex of al)domen. 



ToMicus, Latr. 

 h". Prosternum without or with a very short process 

 between the anterior coxae, 

 (a) Tibiae almost linear, without furrows for the re- 

 ception of the tarsi ; apex of elytra with large 

 teeth in the male, and with a strong impression 

 on each side of suture in the female. 



PiTYOGENEs, Bedel. 

 (A) Tibiae dilated, furnished with furrows for the 

 reception of the tarsi ; apex of elytra without 

 large teeth or deep impressions in the sexes. 



Xylebouus, Eich. 



Genus Crypiialus. 



The members of this genus are very small insects, and may 

 certainly be overlooked by nearly all except the trained economic 

 entomologist. Six British species have hitherto been recorded on 

 poplar, lime, spruce, beech, &c. They are all so very small in size 

 that they cannot be seen to any advantage without the microscope or 

 strong pocket-lens. 



Fowler gives six British species, but as two are rather rare, we may 

 confine ovirselves to four species. As the beetles are exceedingly small 



