254 COLEOPTERA OF NORTH AMERICA. 



Sub-Tribe 7. — JHeloloiitliini (genuini). 



This is the first of the sub-tribes in vvliich the anterior coxa^ 

 are not prominent, but simply transverse, and contained entirely 

 in the coxal cavities. It is distinguished from the other sub-tribes 

 having this character, by the labrum being deeply emarginate, and 

 the ventral segments connate, though the sutures are frequently 

 not effaced. 



The. apical margin of the thorax is never membranous; the 

 fifth ventral segment is connate with the propygidiuin by an angu- 

 lated suture, sometimes partly obliterated; the spiracle is placed 

 at the angle of this suture, nearer the posterior than the anterior 

 margin. The genera indicate two groups, distinguished as fol- 

 lows: — 



Side pieces of metathorax narrow. Rhizotrogi. 



Side pieces of metathorax wide. Melolonth.^. 



Group I. — Rhizotrogi. 



This group is sufficiently distinguished by the labial palpi* 

 being inserted on the under surface of the ligula near the sides. 

 The species are glabrous, or pubescent above ; the thorax is mar- 

 gined in front. The side pieces of the metathorax are narrow, 

 with the epimera moderate in size, or small. One spur of the 

 hind tibiiB is frequently connate with the tibijB in the males, and 

 varies greatly in form according to species. The third joint of 

 the antennge is not elongated. 



The genera are not well defined, and in those having many 

 species considerable variation in the generic characters is seen. 



Some of the species of Lachnosterna, known familiarly under 

 the name June bugs, are very abundant, and do much harm bv 

 destroying the leaves of fruit-trees. 



Claws never serrate, with a single tooth beneath. Lachnosterna. 



Claws more or less serrate, sometimes also toothed. Listrochelus. 



Listrochelus belongs to the interior of the continent, from Platte 

 River to the Colorado of California. Two species of Lachnosterna 

 are known from California; the others all belong to the Atlantic 

 slope of the continent. 



* For an important note concerning the structure of the ligula and posi- 

 tion of the labial palpi in various groups of Melolonthidse, vide DuVal, 

 (ien. Col. Europe, iii. 44. 



