40 j. l, leconte, m. t). 



Mastinocerini. 

 These are small, slender insects, having the antennae biramose, or serrate 

 but not flabellate as in Phengodini, the branches being less slender. The 

 eyes are small, lateral and convex ; the epistome is somewhat convex, and the 

 labruni is small and indistinct ; the mandibles are acute but not prominent. 

 The maxillary palpi are long, the labial very short ; the gula is less deeply 

 excavated than in Phengodes^. The side pieces of metathorax are long 

 and narrow, diagonally divided, with the epimera exposed. The elytra 

 are short, dehiscent, and rounded at tip. 



Antennae ramose. 



Lateral margin of prothorax at-ute : pal])! broad MASTINOCERUS. 



Lateral margin of prothorax obliterated in front : palpi slender... CENOPHENGUS. 

 Antenna- serrate TYTTHONYX. 



MASTII^OCERUS S.dier. 



In this genus the labrum is small and indistinct, and the epistome 

 slightly convex, more advanced than in the two preceding genera ; the 

 head between the eyes is flattened, scarcely concave ; the gula is much 

 less excavated, and the maxillary palpi are long, flattened, not slender, 

 with the last joint triangular or rather securiform. The antenna) are not 

 longer than the head, biramose, with the branches shorter and stouter, 

 though still flexible. The eyes are lateral, moderately large and convex. 

 The flanks of the prothorax are acutely margined, flat, not concave, the 

 edae (if the disc is not maroined nor flattened. The metasternum is 

 longer than usual, with narrow side pieces, but the epimera are large. 

 The elytra are less than one-half as long as the abdomen ; dehiscent and 

 rounded at tip, without distinct epipleurae. Legs slightly compressed ; 

 joints 1 — 4 of tarsi gTadually a little shorter and narrower, fourth small, 

 not lobed beneath. 



% . — Seventh ventral deeply emarginate ; eighth prominent, obtuse. 

 Elongate, uniformly punctured, pubescent, testaceous, abdomen darker, witli the 



last two segments paler : (J unknown): % 6 mm.; Texas texauilS. 



a. — Piceous, head prothorax, legs and last ventral segment dark red. 



I am also indebted to Mrs. King for a larva of Mastinocerus, of slender, 

 cylindrical form and pale color. It was feebly luminous, and lived upon 

 small snails. The perfect insect is thus mentioned in a letter, the observa- 

 tions being made upon a specimen attracted by the lamp : " June 4th saw 

 running rapidly over the table near a lighted lamp, a small Coleopter ; 

 it was twisting its abdomen up over its wings, and evidently trying to 

 straighten them out, as they seemed moist and twisted at their ends. The 

 general appearance suggested Mastinocerus, and acting on this thought, 

 I captured it and sat up till a late hour to be assured of the truth. The 



