Xxil INTRODUCTION. 
of the group inhabits Central America. The groups * Ischyomiides,’ ‘ Osphyides,’ and 
‘ Mycterides’ are represented by one, two, and one species respectively; the two last- 
mentioned groups belong to a northern type. Many of the genera of this family are 
very widely distributed, as Zustrophus, Orchesia, Dircea, Anisoxya, Osphya, and 
Mycterus ; nine, however, are described as new, of which two are from Mexico, and 
one from the State of Panama, the others being of more general distribution within 
our limits, two occurring also in South America. It is probable that several of them 
are really endemic. Three genera are common to North, Central, and South America, 
six to North and Central America, and six to Central and South America. 
The family Pythide has a similar distribution to the Melandryide, but it contains a 
very limited number of species. Seven only, belonging to five genera, have as yet been 
discovered in Central America; of these, three genera and six species are described as 
new. Lecontia (=Crymodes, Lec.) is the largest member of the family occurring 
within our limits; it is a well-known insect of the boreal region of North America, 
extending southward into N.W. Mexico. The other species are of small size, one 
belonging to the widely distributed genus Salpingus. Of the three genera described as 
new, one only, Sosthenes, is likely to be endemic. All are found under the bark of 
trees. 
The family Gidemeride is of considerable extent, and some of its species inhabit 
mangrove-swamps or the sea-shore, where they are found about rotten stumps, piles, 
&c. The Cidemeride is perhaps the most widely distributed of all the families of 
Heteromera, it being represented in many oceanic islands, as well as in continental 
lands. Like the Cistelide, this is a “ neglected” family, as regards the exotic species, 
and up to the date of the commencement of the publication of this work not a single 
representative had been described from within our limits. Ninety species, belonging 
to twelve genera, are enumerated, of which five genera and eighty-four species are 
described as new. Three of the genera (one introduced) are also European, and one 
is certainly represented in various other parts of the World. Ovxacis, Sisenes, Copidita 
Ditylus, Diplectrus, and Microtonus are the principal genera occurring in Centra 
America—Oxacis and Sisenes each with upwards of twenty species; Oxacis and Copidita 
have representatives in the Antilles. The four (new) genera known only as yet from 
Central America are hardly likely to prove endemic. 
The family Xylophilide is probably very widely distributed, at least on continental 
