16 LARV^ OF THE PEIONIN^. 



toothed at upper angle; no striated plate. Labrum roundly cordate, 

 about as wide as long, anterior edge densely covered with short cilia. 

 Antennae long, last joint very long, cylindric, slender. Ocelli three, 

 not very prominent. Palpi slender, tapering; last joint of maxillary 

 palpi equal to that of labial, acutely conical. Postcondylar carina 

 visible. Subfossal spine short, obtuse. 



Posterior area of pronotum coarsely rugose. Eusternal area of 

 pro thorax not distinct in front. 



Pleural disc quite prominent, circular, on first and second abdominal 

 segments less conspicuous, on third and fourth finely rugose. Anal 

 lobes glabrous. Abdominal spiracles oval. 



Pupa: Form as in adult; head glabrous; disc of pronotum sparsely 

 beset with short conical chitinous asperities ; mesonotum and metano- 

 tum glabrous; abdominal tergites sparsely beset with acute chitinous 

 points, these reflexed, some bidentate at apex; anterior margin of 

 third, fourth, fifth, and sixth segments bearing a curved chitinous 

 flangelike carina, and fitting under this on posterior margin of anterior 

 segments are two oval f ovese with protruding rims ; last tergite pro- 

 duced in two latero-dorsal, chitinous, dentate flanges. 



Range: Southeastern Canada, south through eastern and central 

 United States. 



The larva of Orthosoma has been found in dead and decaying logs 

 of practically all arborescent species of eastern hardwoods and 

 conifers. Its chief economic status is the destruction of cross-ties, 

 telegraph and telephone poles, and structural timbers in contact 

 with the ground. It has been described by Packard.^ The adult 

 is found from June to September. 



Derobrachus sp. 



Form as in Orthosoma; integument thick, firm, finely rugose all 

 over body. 



Epistoma scarsely projecting over clypeus at extremities; front 

 produced in four transverse, finely ^vrinkled, blunt-edged tubercles 

 (not round, as in Er gates, nor acute edged, as in Tragosoma) , resembling 

 Orthosoma, except that they are much heavier; mandibles shorter 

 and more robust than in Orthosoma, scarsely rugose, tooth on molar 

 surface not striate. Labrum as in Orthosoma, only thicker, hairs 

 on perimeter; last joint of antennae very short, obtuse conical; basal 

 joint of maxillary palpi larger than next two, last very minute, 

 globular, not one-half length of second; hairs on lacinia and ligula 

 dense. Ocelli three, distinct; postcondylar carina distinct; sub- 

 fossal spine triangularly conical, large. 



1 Packard, A. S. Fifth report of the U. S. Entomological Commission, being a revised and enlarged 

 edition of Bulletin No. 7 on Insects injurious to forest and stiade trees. Wasliington, 1890. Orthosoma 

 hrunneum De Geer, p. 702-703, fig. 238. 



