MALLODON. | 9 
quarters are America, temperate and tropical—species closely allied to Tropical-American 
ones being common insects in Western Africa, and others being recorded from Mada- 
gascar and Arabia. The species have all a similar general form and sculpture, and 
form a most difficult study ; but trustworthy and definite characters may generally be 
found in the mandibles of the males and in the form of the gene, which parts of 
structure have been overlooked by almost all describers. 
1. Mallodon spinibarbe. 
Mallodon spinibarbe, Linn. Mus. Lud. Ulr. p. 67. 
Hab. Mrxtco.—Cayenne, Amazons, SoutH Braziu. 
Received from M. Henri Deyrolle, of Paris, as from Mexico. 
2. Mallodon molarium, (Tab. I. figg. 10, 11.) 
& M. spinibarbi (Lin.) simillimum, at differt margine superiore mandibularum juxta basin tuberculiformiter 
elevato. Elongato-oblongum, subdepressum, nigro-piceum, nitidum ; capitis vertice grosse, epistomate 
subtiliter punctatis; genarum angulis antico-lateralibus productis, sed haud spiniformibus; thorace 
creberrime punctulato, plagis et lineis levibus ut in M. spinibarbi. 
g minor. Mandibule capite haud longiores. 
g major. Mandibule capite dimidio longiores, spatium vacuum magnum ovatum includentes. 
@. Mandibule parve, tuberculo basali minus prominente ; thoracis toto disco levi polito ; cateris ut in ¢. 
Long. 2 usque 3 poll. (mand. incl.) ¢, 1 poll. 9 lin. usque 2 poll. 6 lin. 9. 
Hab. Mexico (Sallé); Nicaragua (Belt, Janson) ; PANAMA.—COLOMBIA. 
The figures are from Chontales specimens. 
The males of minor development bear the closest possible general resemblance to 
the same sex of I. spinibarbe ; but they may be readily distinguished by the form of 
the upper edge of the mandibles. In M. spinibarbe this edge describes an upward 
curve from the base; whilst in JZ. molarium there is a tubercular prominence at the 
base, after which the edge describes a downward curve; the result is to give a much 
greater vertical development to the mandible of If. spinibarbe as compared with that of 
M. molarium. Inthe males of greater development these peculiarities are still more 
strongly pronounced; and I have not seen males of If. spinibarbe with mandibles of 
the great length and curve which seem common in M. molarium. In the dentition of 
the inner side both species are very similar, presenting a little below the acute apex 
two obtuse teeth. There is another but minor specific difference in the form of the 
angles of the gene or cheeks below the insertion of the mandibles: in both species 
the edge is slightly sinuated, and the angle forms a projection visible when the head 
of the insect is viewed from above; but in VW. molarium the angle is blunt, whilst in 
M. spinibarbe it is developed into a distinct stout spine. 
3. Mallodon angustatum. 
Mallodon angustatum, Thoms. Physis, i. p. 100. 
Hab. Mexico; Guatemata, Chinautla, 4100 feet (Salvin), Capetillo (Champion) ; 
Nicaragua, Chontales (Belt, Janson). 
BIOL. CENT.-AMER., Coleopt., Vol. V., Vov. 1879. | c 
