206 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
ing about in logs or on the forest floor. The head is provided with 
grasping mandibles, or in many forms the mandibles are fitted for 
sucking, having a hollow longitudinal canal or composed of two longi- 
tudinal pieces, one sliding within the other. The ventral mouth parts 
are deeply retracted and the various parts more or less fused or 
atrophied. The labrum is fused with the clypeus into a nasale. Many 
of these larvae have luminous spots along several of the body segments 
or grouped in the caudal segments. , 
Evos trilineatus Melsh., E. aurora Ubst., Plateros spp., and Calopte- 
ron reticulatum F. are fr equently seen on vegetation along the edges of 
a wood. The larvae are found in wet, well-rotted logs where they 
probably feed on decaying vegetable matter. The luminous larvae of 
species of Phengodes, Chauliognathus (fig. 44), Caeniella, Cantharis, 
Photurus, Photinus, and Podabrus often attract attention crawling 
about on the damp ground. The adults of many of these forms are 
predaceous. Some occur commonly on vegetation. 
Famity MELOIDAE 
The Blister Beetles 
The more common forms of blister beetles that are found eating 
forest vegetation are fairly large, soft-bodied, loose-jointed, sprawling 
beetles (Blatchley, 47), of vari iable color, often green, gray, brown, or 
black, having a broad head on a distinct neck, soft elytr a, abdomen 
often large and swollen, and tarsal claws cleft and appendaged. ‘The 
larvae are parasitic on the egg masses of grasshoppers or in the nests 
of bees, and consequently rarely seen unless particular search is made 
for them. 
The first-stage larva, the triungulin, is peculiar among the Coleop- 
tera. The staphylinoidlike form differs markedly from the later sem1- 
parasitic stages. The triungulins are very active and well adapted to 
their search for a particular host. Some ascend to the flowers of plants, 
where they attach themselves to the hairs of visiting bees and are thus 
carried to the bees’ nests. Another stage of the larva may be scara- 
baeoid in form, and the final stage superficially resembles the larva of a 
bee or wasp. The larvae of very few species are known. 
Although the larvae may be injurious in bees’ nests or beneficial in 
destroying grasshoppers, the adults of many forms feed on foliage and 
are very destructive when abundant. Anatomical details of the Jarvae 
are not given, as they are seldom seen by the forester and are not 
treated in the key. Serious damage by the adults of such forms as the 
striped blister beetle (/picauta vittata (F.)), the margined blister 
beetle (2. marginata (F.)), Macrobasis fabrictt (Lec.), I. unicolor 
(Kby.), Pompnopoea aenea (Say), and P. sayi Lee. often occurs to 
young trees in nurseries and to ornamental plantings, especially in 
the Middle West. For control measures suitable for use against these 
beetles see page 35. 
Famity BOTHRIDERIDAE 
The Cocoon-Forming Beetles 
The Bothrideridae are separated from the Colydiidae, with which 
they are often grouped, by their depressed form, 11-jointed antennae, 
widely separated coxae, and long first tarsal joint. The larvae are 
