CISTELID A. 885 
Fam. CISTELIDA. 
The tropical forms of Cistelide have been much neglected, and the majority of the 
species existing in collections are still undescribed. Nota single species has been as 
yet described or noticed from any part of Central America*, though the family is very 
numerously represented in every part of the Neotropical Region. Lobopoda is perhaps 
the most characteristic genus of Cistelide in the New World; it contains upwards of 
forty species in Central America. Hymenorus also contains a large number of species 
in our region, though it is of a much more northern distribution and does not extend 
south of Nicaragua. The “ Lystronychides,” the genera of which contain the most 
characteristic forms of the Tropical-American Cistelide, are poorly represented in 
Central America; the species of this group are usually more brightly coloured, and in 
one genus (Prostenus) the antenne have their outer joints greatly dilated and flattened. 
The group ‘“‘ Cteniopides,” in which the sixth ventral segment is extended beyond the 
fifth and visible in both sexes, is not represented in Central America. The Cistelide 
are numerous in both the Old and New Worlds and a very large number inhabit 
Australia. Nearly the whole of the Central-American species are described as new, 
and many new genera have been required for them. ‘These insects are found upon 
trees or herbage and also beneath the loose bark of trees; no doubt the earlier stages 
of many of the species are passed in decaying timber. . 
Excellent specific characters exist in many of the members of this family in the 
structure of the secondary sexual organs of the males; and in the genus Lobopoda 
these characters are of great assistance in discriminating the very numerous closely 
allied species. These parts being very hard and chitinous they can be extracted and 
examined with very little difficulty, and they are frequently extruded at the time of death. 
Numerous specimens of the same species have in some cases been examined and the 
structure proves to be invariably constant, the only variation being a little in degree. 
The sixth or last ventral segment, which in the Central-American Cistelide is usually 
completely hidden beneath the fifth in both sexes, is in many genera greatly modified 
and has on either side a long projecting lobe; these lateral lobes no doubt form clasping- 
organs, and they vary greatly in shape (sometimes being of a very complex character) 
according to the species. Above and on either side of the long chitinous central sheath 
containing the intromittent organ (and quite independent of the lateral lobes) a stout 
chitinous piece more or less rounded off at the end and concave within is visible: these 
pieces are connected above by membrane, and are more or less approximate when the 
* The genus Blepusa was established by Prof. Westwood (Trans. Ent. Soc. Lond. iii. p. 69) upon a single 
species, B. costata, the exact locality for which was not certainly known; the insect was supposed to be from 
‘‘Mexico or some adjacent part of South America.” It cannot be regarded as belonging to the Central- 
American fauna. 
BIOL. CENTR.-AMER., Coleopt., Vol. IV. Pt. 1, August 1888. 3 DD 
