8 
NORTH AMERICAN THROSCIDAE 
witliin the outer carina; lobe margined in front, sparsely, rather coarsely punc- 
tate; flanks coarsely, not closely, variolate punctate, with hairs. IVIeso-meta- 
sternal suture fine but distinct. Mesosternum smooth, impunctate and 
glabrous narrowly along the middle and along the posterior margin, sparsely, 
gradually more coarsely punctate at sides, the punctures bearing short hairs; 
a somewhat sinuous impressed line reaching from middle coxae obliquely two- 
thirds toward outer hind angle of metasternum. Anterior and middle coxae 
deeply inserted and narrowly separated by the prominent lateral extension of 
the mesosternum. Episterna of metasternum very narrow and impunctate in 
front, a little wider and punctate behind; epimera not visible. Abdomen 
finely, rather closely punctate and pubescent, punctures a little coarser on last 
segment; segments one to four equal, fifth longer, with apex strongly arcuate. 
Legs black, finely, sparsely punctate and pubescent. Length 4.5 to 4.75 mm. 
Lower California: Santa Rosa; El Taste. 
This species is only equalled in size in our fauna by Aulono- 
throscus valiclus and Pactopns hornii. In the Biologia Dr, Horn 
says of the very fine antennal stria in certain species that it is 
sometimes present, at others absent. The few specimens taken 
by Mr. Beyer all show it, but it is possible examples may occur 
without it, 
THROSCINI 
In this tribe the mandibles are entire and acute at tip, the 
antennae clavate, or in Pactopus fusiform, in repose resting in 
open grooves extending along the prosternal sutures, thence 
bent outward across the posterior part of the flanks of the pro- 
thorax nearly to the side margin; the prosternum is truncate; 
the anterior and middle trochanters are short; the anterior 
femora, have a distinct angle, and the middle femora a denti- 
form angle at base on the upper side, serving to yet more firmly 
fix the femur when retracted. This structure was called to my 
attention by M. Fleutieux, to whom it was communicated by 
M. Louis Bedel. The mesosternum at middle before the fossa 
is produced in a prominent vertical lamina (recalling the structure 
seen in Philhydrus) , against the compressed and excavated sides 
of which rest the anterior coxae, while the free angle forms the 
striking point for the prosternal spine, which when released slips 
along the lower surface into the meso-fossa as in Elateridae. 
PACTOPUS Latreille 
Besides the characters in the table and in the description 
below, it should be mentioned that the middle and posterior 
