264 INSECTS. COLEOPTERA. 



Gen. LISSODA. 



2. Joints of the tarsi not furnished below with prolonged cushions or lobes ; anten- 

 na? generally distant at their origin. 



A. Labrum and mandibles entirely concealed by the anterior extremity of the pre- 

 sternum ; fore part of the widened hood transverse ; antennae more approximat- 

 ed at the base than the following. 



a. No groove on the lateral margins of the thorax. 



Gen. CRYPTOSTOMUS, NEMATODUS, (Elater filum.) 



b. A groove on each side under the lateral margins of the thorax to receive the an- 

 tennae. 



Gen. EUCNEMIS, {Elater deflexicollls.) 



B. Labrum and mandibles discovered, at least above. 



a. Anterior extremity of the epistome sensibly more elevated than the base of the la- 

 brum, and often forming an edge or sharp margin. 



* Head free, as broad or broader than the anterior margin of the thorax ; eyes much 

 projecting ; body linear. 



Gen. EXOPHTHALMUS, {Elater mesomelas, linearis, &c.) 



** Head sunk to the eyes in the thorax, narrower at its base than the anterior mar- 

 gin of the thorax. 



Gen. HEMIRHIPES, (Elater ttneatus;) ELATER. 



b. Anterior extremity of the epistome on a level with the base of the labrum. 



Gen. LUDIA, (Elater ferrugineus, and others.) 

 II. Antennae terminated in a perfoliated club of three joints. 

 Gen. THROSCUS 



Gen. ELATER, Lat. Lin. 



Antennae serrated ; head sunk to the eyes in the thorax ; tho- 

 rax almost as broad as the elytra ; mandibles notched or bifid ; 

 palpi with the last joint largest and triangular ; feet partly 

 contractile, and the tarsi with the joints entire. 



The Elaterides are found everywhere, on flowers, plants, and on the trunks and 

 under the bark of trees. They are taken easily, but often avoid seizure by drop- 

 ping to the ground. They are all provided with wings, but are generally found 

 walking very sloTvly. The insects of this genus possess the faculty of leaping up- 

 wards perpendicularly when placed on their back, and falling nearly in the same place. 

 This is effected by a particular mechanical structure of the body, and the purpose of 

 the effort is to recover their position on the feet. 



E. noctilucus, Lin. Ohscure brown, with cinereous down ; a yellow 

 round convex spot on each side of the elytra, near its posterior 

 angles ; dotted striae on the elytra. One inch long. Inhabits South 

 America. Oliv. Col. ii. 31. 

 The two yellow spots on this insect give a brilliant light, sufficient to read by when 



a number of them are together. The E. phosphoreus possesses the same qualities. 



E. ceneus, Lin. Shining bronze green, with the elytra striated, and 

 the feet fawn-coloured. 6 lines long. Inhabits Northern Eu- 

 rope. Oliv. Col. viii. 83. 



E. Germanus, Lin. Bronze green, with the feet black. 6 lines long. 

 Inhabits Europe. Oliv. Col. ii. 12. 



E. caslaneus, Lin. Black ; thorax covered with a reddish down ; 

 elytra yellowish, with the extremity black ; antennae pectinated 

 in the males. Inhabits Europe in woods. Lat. Gen. i. 249. 



