8 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



the specimen in the light in tlie most convenient position I have 

 examined the tarsi with a hand lens, for the small species using the 

 compound microscope. The first three joints of the anterior and 

 those of the middle tarsi should be most carefully examined under 

 different angles of illumination. Many specimens have the hairs or 

 spinules rubbed off; if possible use perfect specimens. 



A stud}'' of the mouth-parts, while exceedingly desirable for the 

 purpose of correlation with the genital parts, is not possible without 

 dissection and mutilation of the specimens. In many instances, 

 nevertheless, this has been done, especially when the material war- 

 ranted it. 



Caution. — The student must bear in mind not to accept measure- 

 ments representing length, breadth, and thickness in a literal sense, 

 but only as indicati\e of relative proportions. 



GENERAL EXTERNAL ANATOMY. 



The following results have been obtained chiefly rom a study of 

 Eleodes dentipes. 



Form variable. Integuments usually strongly chitinized. 



Head (Plate 8, fig. 1) quadrate, nearly encircled by a rather broad 

 impression, which is strongly marked behind the gular peduncle 

 and buccal fissures, less so behind the tempora, someti.nes feebly 

 indicated across the dorsum. By this impression the epicranial wall 

 is divided into two regions, the occipital and fronto-buccal. The 

 epicranial sutures are mostly obsolete. 



The ()ccipit(d region is globular and condylar, and the surface more 

 or less finely granulato-punctate ; the foramen usually vertically 

 oval, sui:)erior margin bisinuate, sinuations separated by a median 

 subtriangular process, inferior margin broadly sinuate and straight 

 between the gular sutures. The superior and visible portion of this 

 region forms the vertex. 



Fronto-hi(ccal region moderately depressed, surface lines converg- 

 ing to UK'cl about a length of the region in advance. Frons more or 

 less ti'ansverse, never strongly convex; limited laterally by the eyes 

 and the more or less prominent and arcuate preocular frontal ridges, 

 which thicken and descen<l in front of the eyes to their inferior 

 fourth, articulating with the genu' below. The inflexed and externo- 

 anterior sui'face of the fi-ontal ridges are excavated, forming the 

 antennal fossa^ the anterior margins of which bear a narrow oblong- 

 oval mandibulai" condyle, just behind the lateral frontal suture. The 

 anterior frontal margin is deeply emarginatc, middle thi'ee-fifths of 

 the emargination straight, sides prominent anterioi'ly forming the 

 frontal angles, the internal margins of which are straight and an- 

 teriorly divergent, forming an obtuse angle with the middle of the 



