Famity—CETONIUD. Sus-FamiLy—CREMASTOCHEILIDES. 57 
The trophi of this genus are carefully represented by Dr. Burmeister in his ‘Genera XL, Ins.’ No. 9, pl. I, 
figs. 6, 7. My figures were made from a dissection of the type specimen sent to me by Dr. Schaum. The max- 
ill (pl. II, fig. 4.2) have the galea very acute, and the tooth of the mando thickened above its apex ; the men- 
tum is represented as seen within the mouth in fig. 44, shewing the position of the small square basal portion in 
the middle with the palpi arising in front of its lateral anterior angles. Fig. 4c represents the mentum seen 
from behind, shewing the small square basal portion in relief, and fig. 4d represents the anterior tibia and tarsus, 
of which the two basal joints are concealed by the apex of the former. 
Genus 26—CREMASTOCHEILUS. 
(Knoch, Neue Beytr. 1801, p. 115.) 
Corpus obscurum depressum superficie variolosa ; antennz articulo basali magno subtrigono apice dilatato ; 
clypeus magnus transversus margine antico elevato; mandibule mediocres, parte cornea externa curvata et 
obtusa, apice ipso acuto, et partem internam membranaceam ambiente; maxilla basi crass, galea uncinata 
acuta, mandone brevi acuminato in dentem transversum acutum abeunte; mentum maximum, parte basali 
angusta, apicali vero latissima pateriformi excavata, margine ejus postico interdum profunde emarginato aut sub 
jugulo in processum corniformem retro deflexo (pl. XIV, fig. 5¢, 5); prothorax angulis anticis et posticis ine- 
qualibus vel tuberculatis: spiracula 2 apicalia conica; prosternum in spinam parvam compressam ante coxas 
anticas porrectum (pl. XIV, fig. 4a); mesosternum tenue muticum inter coxas medias angustissimum ; 
tibie antice bidentate ; tarsi 5-articulati simplices. 
The species of this genus are confined to North America. They are divisible into three groups, according 
to the form of the mentum. 
Grove A. Those in which the hind margin of the mentum has a very deep notch, and which appear 
to be confined to the Atlantic slope as far as the Platte River. The species belonging to this Group may be 
considered as the types of the Genus. 
Grove B. Those which have a very small notch or incision in the hind margin of the mentum. 
Group C. Those with the hind margin of the mentum entire and pointed, and which are distributed from 
the Platte River to the Pacific Ocean. 
The following tabulation, by Dr. Horn, of the American species with which he was acquainted, will be 
found useful in the determination of this very difficult group. It will be seen that the insects described below, 
under the names of Cr. Mewxicanus and Cr. crenicollis (belonging to the third group), and Cr. cicatricosus, Cr. 
junior (if distinet from Cr. squamulosus), and Cr. Percheronii, belonging to the second group, are omitted. They 
are introduced in this work mainly on the authority of Dr. Schaum, who possessed specimens of them, and 
who was in an excellent position to judge of their specific rank, both from possessing the typical specimens 
of Gory, and from his actual acquaintance with the American Collections made during a long visit to the 
United States. Being unable to examine the specimens on which these additional species were founded, and 
to compare them with the more recently published descriptions of Drs. Leconte and Horn, I have not ventured 
to introduce them into this table. 
The first three species, Cr. planatus, depressus, and saucius, have a short frontal carina joining the reflexed 
ridge in front, while the first two have the sides of the head carinate and a transverse occipital groove, and 
the pygidium elevated longitudinally. The two species just cited are very decidedly ambulatorial, from the 
form of their legs, which are relatively longer than any others of the genus. ‘The anterior tibie are slender, 
slightly arcuate, and the teeth of the outer edge small or obsolete. The tarsi are longer than the tibia, and 
the anterior pair with the peculiar formation indicated in the table. The dorsum of the elytra is also perfectly 
3 flat and bounded laterally by a slightly elevated border. 
I 
