THE METALLIC WOOD-BORING BEETLES. 



795 



Tribe III. MASTOGENINI. 

 This tribe is represented in North America by the single genus 



XII. Mastogenius Sol. 1851. (Gr., ' ' mother + chin.") 



It in turn is represented in the eastern United States by one of 

 the smallest Buprestids known, subcylindrical in form and having 

 the antennas inserted in large cavities, narrowing the front, which 

 does not expand again in front of the cavities as in Agrilus; mouth 

 small, deflexed but not applied to the prosternum ; thorax truncate 

 at base, closely fitting against the elytra ; prosternum truncate be- 

 fore and behind, with the lateral sutures parallel; scutellum small, 

 triangular; legs not contractile, claws broadly toothed. 



1511 (4717). Mastogenius sf/bcyanefs Lee, Trans. Amer. Phil. Soc, XI, 

 1859, 254. 



Subcylindrical. Bluish-black, shining. Head with a lengthwise groove. 

 Thorax one-half wider than long, slightly wider than elytra, convex, sides 

 strongly rounded ; surface, as well as that of elytra, finely and rather 

 sparsely punctate. Elytra with a deep but narrow transverse impression 

 at base, sides parallel, tips obtusely rounded. Length 2-2.5 mm. 



A single specimen taken by sweeping on University farm near 

 Mitchell, Lawrence County. May 11. LeConte states that it oc- 

 curs rarely on leaves and flowers in the Middle, Southern and West- 

 ern States. 



Tribe IV. AGRILINL 



Small-sized, usually slender, though sometimes short, broad and 

 flat species, having the body narrowed on apical third. Their chief 

 structural characters are the front strongly narrowed by the inser- 

 tion of antenna, then expanded, thus forming two diverging lobes ; 

 front part of head vertical, the mouth inferior and applied to the 

 prosternum in repose; thorax lobed at base, receiving the convex 

 bases of the elytra; legs contractile; tarsal claws strongly toothed. 

 Six genera are recognized as composing the tribe, four of which are 

 known to be represented in Indiana, while another perhaps occurs. 



KEY TO INDIANA GENERA OF AGRILINI. 



a. Antennae free, in repose not received in grooves on the under side of 

 thorax. 



b. Hind tarsi with first joint scarcely elongated. Efpristocerfs. 

 1)1). Hind tarsi with first joint as long as the three following. 



XIII. Agrilus. 



aa. Antennae received in grooves on under side of thorax near the margin. 



c. Scutellum small ; tibiae linear. 



