LUCANID/E : STAG-BEETLES. 



3. Length, .75 in. or more Lucanus. 



Length, usually not more than .5 in.; elytra with traces 



of longitudinal grooves Platycerus. 



4. Antennae elbowed at end of first joint, which is nearly 

 or quite as long as all the others united 5. 



Antennas straight 6. 



5. Length, more than .5 in.; eyes strongly notched by the 

 margin of the head Dorcus. 



Length, less than .5 in.; eyes not strongly notched. 



Platycerus. 



6. Length, more than I in.; front of head with a short 

 bent horn on head Passalus. 



Length, less than i in.; no horn on head. . . .Ceruchus. 



Lucanus It is only the males which have abnor- 



mally long mandibles. L. elaphus is a 

 southern species which gets as far north as New Jersey and 

 Indiana. The mandibles of the male are as long as the 

 abdomen. The female may be separated from the other two 

 species mentioned by her black legs and chestnut-brown 

 elytra. Length of male (not including mandibles), 1.3 to 

 1.6 inches; of female, about 1.2 inches. L. dama (Plate 

 LXXIX), the common species near New York: like 

 placidus, the mandibles of the male are only about as long 

 as the thorax ; each mandible has but one tooth on the inner 

 side; the head of the male is broader than the thorax; 

 femora, light brown; length, I to 1.4 in. The mandibles 

 of the male placidus, a species said to be common in the 

 Mississippi Valley but rare along the coast, are straight 

 and have several teeth on the inner side; the head of the 

 male is not broader than the thorax; the femora are dark 

 brown. 



Dorcus parallelus: brownish black; male's head nearly 

 as broad as the pronotum, female's narrower. 



Platycerus quercus: blackish or dark reddish-brown; 

 male's mandibles as long as the head, longer than the 

 female's, and with about six teeth at the tip; grooves on 

 elytra usually reduced to three or four faint ones near the 

 suture. Found most frequently under bark of, as its 

 name indicates, oak. 



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