208 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
radically different from the colydiid forms, both in structure and 
habits. The body is of the soft-textured, spindlelike type, associated 
with parasitic habits, and has short fleshy legs; the ninth abdominal 
segment bears two recurved spines; the mandible is without a molar 
structure, and bears a small hook. These larvae are predaceous or 
parasitic on wood-boring larvae. After consuming the body contents 
of their host, they form oval, depressed, semitransparent cocoons on 
the walls of the burrows, in which the larvae pupate. 
Bothrideres geminatus (Say) is an eastern species attacking borers 
in hardwoods. Deretaphrus oregonensis Horn, of similar habits, at- 
tacks wood borers in conifers in Oregon and California. 
Famiry CATOGENIDAE 
Catogenus rufus (F.) 1s a very common beetle under the bark of 
both hardwood and coniferous trees and peculiar in that its larva is 
parasitic on the larvae of wood borers. They are usually found in the 
pupal cells of the host. The adult is extremely variable in size, from 
5 to 12 mm., probably depending on the food material secured by the 
larva. It is elongate, depressed, and reddish brown. The head has 
a transverse groove behind the eyes; the thorax narrows behind and is 
impressed with a median line posteriorly. The elytra are deeply 
striate. The larva is soft-bodied, white, spindle-shaped, with weak 
conical legs and small recurved hooks on the ninth tergum. The 
mouth parts are not retracted, the mandible bears a hook but no 
molar structure, and the labial palpi have only one joint. Scalidia 
linearis Lec. is similar in habits and larval characteristics to C. rufus. 
It has been observed feeding on bostrichid larvae in Acacza in southern 
Texas. 
Famity NITIDULIDAE 
The Sap-Feeding Beetles 
The Nitidulidae, are small, oval, depressed beetles, rarely 10 mm. in 
length, and usually not half that size, often of contrasting shining 
black, red, and yellow colors. They have club-shaped antennae and 
the sides of the thorax and elytra are often margined, the latter fre- 
quently truncate at the tips, exposing the abdomen. The larvae are 
elongate, depressed, and usually yellowish white, but sometimes col- 
ored, havi ing five-jointed legs, bifore spiracles borne on short tubes, and 
the ninth abdominal seoment often bearing paired and forked horny 
armatures. The head is broad and projecting with deeply retracted 
mouth parts. The mandible is provided with a molar structure and 
hook. 
Both beetles and larvae feed on decaying and fermenting juices 
under bark or on those exuding from fr eshly cut logs or wounds on 
trees. Some are reported to be predaceous, but the writer’s observa- 
tions show no confirmation,of this report. Many forms are common 
on fungi, decaying fruits, and dead animals. 
Colopterus truncatus (Rand.), Colopterus unicolor (Say), Carpo- 
philus niger (Say), Carpophilus marginatus Er., and Prometopia sex- 
maculata (Say) are ar ped uen ay met with on freshly cut logs and sappy 
wounds, where they attracted for feeding. Glischrochilus fasci- 
atus (Oliv.), G. Pe oe (Oliv.), G. confluentus (Say), and 
