490 COLEOPTERA OF NORTH AMERICA. 



Tribe XVIII.— TACHYGONIIVI. 



This tribe contains a few small species, which in form and 

 characters are among the strangest insects of the family. The 

 body is broadly ovate, rather depressed above, and ornamented 

 with tufts of hair; the prothorax is comparatively small, much 

 narrowed in front. The head is small, the eyes large, and the 

 front very narrow, as in Zygopini ; the beak is rather short and 

 stout- as in certain Ceutorhynchini, and retracted upon the pro- 

 sternum, but the autennse are straight, inserted near the base of 

 the beak, not geniculate, and the first joint (scape) is no longer 

 than the second; this is followed by five short joints, gradually 

 increasing in width; the club is elongate-oval, distinctly aunulated. 

 The front coxte are subconical, prominent, and widely separated, 

 so as to leave a space in which the beak rests when retracted. 

 The middle coxae are about three times more separated than the 

 front coxae, and the raesosternum is very short, transverse, and 

 perpendicular to the general surface of the metasternum, which is 

 still wider. The side pieces of the mesosternuin are large and 

 distinct, those of the metasternum are narrow. The hind coxie 

 are oval, more widely separated than in any other tribe known to 

 us, and near the side margin of the elytra. The first and second 

 ventral segments are very large and connate; the third and fourth 

 very short; the fifth is nearly as long as the second, rounded be- 

 hind. The pygidium is exposed, and suddenly declivous at tip, 

 presenting the appearance of an anal segment in both sexes. The 

 front and middle legs are slender and moderate in length, the 

 til)iee armed with a terminal hook; the third joint of the tarsi is 

 very widely dilated, the fourth joint as long as the first, with 

 divaricate and appendiculate ungues. The hind legs are much 

 longer and stouter, so as to clasp the leaves upon which the 

 insect rests. 



The geographical distribution is remarkable; a few species of 

 Tachygonus in America; one species of Dinorhopala in Birmah. 

 This fact, and the extraordinary characters above detailed, indi- 

 cate the preservation of an ancient form, which, althougii having 

 the affinities mentioned, is equally out of place in any position in 

 a linear arrangement. 



Four species ot Tachygonus are found in the southern and 

 interior parts of the Atlantic region. 



