376 Mr. H. W. Bates on Longicorn Coleoptera. 
their form is only an exaggeration, or an extreme deve- 
lopment, of the well-known structure, common in the 
males of the group, in which the third to fifth joints are 
more or less swollen. In Bolbotritus the bulbous enlarge- 
ment of the third joint is enormous, encasing in its apex 
the enlarged third joint, and even to some extent, also the 
fifth, which appears only as a prominent tubercle at the 
end of the bulb ; and this excessive enlargement appears 
to have been obtained at the expense of the remaining 
joints of the antenne, which are extraordinarily short- 
ened. The insect is interesting, as an illustration of the 
tendency so wonderfully displayed by the Longicornia 
to extreme developments of any variable feature, in species 
otherwise closely allied. This tendency is carried some- 
times to such a length, that the affinities of the modified 
forms are no longer recognizable, and hence the unusual 
difficulties often complained of as attendant on their 
classification. 
Mallaspis preecellens, n. sp. 
M. Beltii affinis, multo angustior et gracilior. Leete 
zenea, nitida; capite aurato valde elongato grosse haud 
profunde subrugoso-punctato, supra late sulcato; antennis 
corpore vix brevioribus, articulis basalibus auratis, 6-7 
violaceis, reliquis nigris, omnino linearibus, punctatis, 3-4 
paulo latioribus subplanatis, 6-7 breviter sparsim denti- 
culatis; thorace quam in M. Beltii multo angustiori, spina 
mediana valida, antice et postice sequaliter angustato, 
supra discrete passim punctate; scutello lete aureo- 
sericeo ; elytris elongatis postice paulo angustatis, supra 
basin ad paulo convexis creberrime subtiliter ruguloso- 
punctatis, basi multo levioribus nitidis ; pedibus elon- 
gatis, sneo-auratis, tarsis violaceis; femoribus anticis 
grosse granulatis ; corpore subtus cupreo-zneo splendido. 
Long. 1 unc. 8 lin.; lat. pone humeros 6 lin. ¢. 
Hab.—Chiriqui, near Panama. 
Two specimens in the British Museum, and one in my 
own collection. The species is very distinct from all 
hitherto known. The rich intense metallic hues of its 
antennee and legs, at once distinguish it from all others 
having linear antennal joints. 
