438 | BRUCHIDES. 
the extreme northern and southern points of our region, though so widely separated, 
than there is between the Mexican province and the adjacent United States region. 
This conclusion is, however, invalidated by two great facts: first, that the Bruchides 
of the United States have not been thoroughly collated with those from our region 
(owing to the very imperfect condition of collections of this family a great many of the 
North-American species are quite unknown in Europe), so that there may be a greater 
community than is yet ascertained ; second, that the borderland, where the greatest 
community between the two regions will be undoubtedly found to exist, has been 
inadequately explored. 
BRUCHUS. 
Bruchus, Linneus, Syst. Nat. ed. xii. p. 604; Schdnherr, Syn. Ins. Cure. i. et v. 
Kytorhinus, Fischer, Mém. Soc. Imp. Mose. ii. p. 298. 
Pachymerus, Latreille, Fam. Nat. Régne anim. p. 386. 
Adromisus, Gozis, Bull. Soc. Ent. Fr. 1881, p. exiii. 
Andromisus, id. Rev. d’Ent. iv. p. 125. 
After separating Caryoborus this genus will still comprise about 500 described 
species, and is found in most parts of the World. The study of the insects of this 
genus is at present a matter of great difficulty, no recent monographer having dealt 
with it, and the arrangement suggested by Schénherr for the comparatively small 
number of species known to him being eminently unsatisfactory. Indeed all the 
structural characters appear to grade off again and again in the genus, so that no one 
of them, as far as I have observed at present, can serve the purpose of dividing the 
species even in a preliminary manner. The specific distinctions in fact frequently 
consist of modifications of the very characters that have been used to define the groups 
of species. Schénherr relied on the dilatation of the femora and on the shape of the 
thorax, but each of these characters is among the most variable of the genus. Dr. Horn 
has lately employed the denticulation of the hind femur with satisfactory results so far 
as the North-American species are concerned ; but this will not help much as a means 
of facilitating determination of the more numerous species found in our region. In 
our species the normal denticulation of the femur in the genus appears to be one long 
tooth and two small denticles, and this character occurs in several forms that in other 
respects are very dissimilar; but, on the other hand, species that are very closely allied 
differ in the number of denticles. The femoral denticulation, therefore, though of 
great importance, can only be employed in subordination to other characters, and its 
value in any case as a means of arrangement is largely discounted by the great number 
of species that fall into the category of one tooth and two denticles; thus it happens 
that Dr. Horn in arranging the North-American species into nine groups, has to place 
half the species in one of these. I have, for the purpose of facilitating the labour of 
