THYREOCEPHALUS. 499 
thorax, and the fact that these are nearly conjoined behind the prosternum, are 
sufficient to validate the genus. It is probably peculiar to Tropical America; though 
some of the Malasian and Papuan insects (X. lorquint, Fauv., e.g.) approach it closely, 
I think it more probable that they will form a distinct genus. The Amazonian Linidius 
tenuipes and L. extremus, Sharp, are also Thyreocephali. ‘The genus is by no means 
homogeneous, and its study is a good deal complicated by the sexual differences being 
very considerable, and the insects themselves very rare. 
1. Thyreocephalus salvini. (Tab. XIII. fig. 3.) 
Nigerrimus; elytris cyaneis, nitidis, fortiter punctatis; capite magno, disco post sulcos frontales fortiter 
punctato. 
Long. 18-20 millim. 
_ Hab. Panama, Volcan de Chiriqui 4000 to 6000 feet (Champion). 
Head depressed, black and shining, coarsely punctured at the sides and vertex, and 
also with a similar coarse punctuation extending backwards behind the frontal grooves. 
Thorax very shining, straight at the sides, with rather numerous punctures near the 
front and side margins. Elytra shining blue, somewhat sparingly and irregularly, though 
coarsely, punctured. Under surface of the head with a few coarse, distant punctures. 
In the male the head is broader, so as to attain twice the width of the thorax, and 
the vertex is more rounded, the interantennal space bearing the labrum is broader, as 
is also the labrum itself, and the mandibles are longer and more slender. 
Two males and one female were secured ; an example of the former sex is figured. 
2. Thyreocephalus subtilis. | 
Nigerrimus; elytris nigro-cyaneis, subopacis, subtiliter punctatis; capite magno subtiliter punctato, ad latera 
et ad verticem punctis majoribus impressis. 
Long. 17 millim. 
Hab. Panama, Volcan de Chiriqui 3000 to 4000 feet (Champion) —Sovutn America, 
Venezuela (coll. Sharp). 
Only one example of this species has been obtained in our region; but I have a small 
series in my collection from Venezuela. T. subtilis, though closely allied to T. salvini, 
is easily recognizable by the different punctuation of the head and elytra. The examples 
exhibit sexual distinctions similar to those of 7. salvinz, the individual captured by 
Mr. Champion being a small male. - 
8. Thyreocephalus lynceus. 
Xantholinus lynceus, Er. Gen. et Spec. p. 309". . 
Hab. Nicaragua, Chontales (Belt); Panama, Volcan de Chiriqui 2000 to 4000 feet 
(Champion).—CotomB1a, Bogota + (coll. Sharp). 
An example taken by Mr. Belt differs a little from the two specimens found by 
3 SS 2 
