SILUSA. 277 
This insect appears closely allied in structure to S. hirtella, and, like it, has quite the 
facies of the well-known S. rubiginosa; it differs much, at first sight, from S. hirtella, 
in consequence of the dark colour and coarser sculpture. Only a single individual has 
been found. 
6. Silusa opacella, (Tab. VI. fig. 17.) 
Subparallela, nigro-fusca, opaca, obsoletissime punctata, pedibus sordide testaceis; antennis crassiusculis, 
articulis 4°-10™ fortiter transversis. 
Long. 3-34 millim. 
Hab. GuateMALA, Totonicapam 8500 to 10,500 feet (Champion). 
Antenne short and stout; the three basal joints very obscurely paler than the others ; 
third joint rather shorter than the second; fourth to tenth transverse; terminal joint 
stout. Head a good deal narrower than the thorax, dull, invisibly punctate. ‘Thorax 
strongly transverse, dull, invisibly punctate. Elytra a good deal longer than the 
thorax, dull, very obsoletely punctured. Hind body densely punctate, the sculpture 
not quite so obsolete as on the more anterior parts of the body, and on the apical 
segments a little less dense than on the basal ones. 
This insect has a very Homalotoid appearance, and agrees with the genus Homalota 
in the structure of the sterna, the middle coxz being contiguous, and the meso- and 
metasternal processes widely separated. The basal joint of the posterior tarsus is short, 
but distinctly longer than that following it. ‘The male has a tubercular carina on the 
middle of the sixth dorsal plate, and the hind margin of the following plate provided 
in the middle with four or five closely placed prominent teeth, and at each side with a 
more remote tooth. 
7. Silusa gracilis. (Tab. VI. fig. 18.) 
Elongata, nigerrima, parcius pubescens, nitida ; antennis fuscis, basi rufo ; pedibus piceis, tarsis dilutioribus ; 
prothorace parum transverso, anterius angustato, fortiter punctato; abdomine parum punctato, segmentis 
2°-5™ basi profunde, transversim depressa. 
Long. 43 millim. 
Hab. Guaremata, Quiche Mountains 7000 to 9000 feet (Champion). 
Antenne slender at the base, a good deal thickened outwardly; third joint as long 
as the second; fourth quite slender, longer than broad ; fifth quite as long as broad; 
tenth rather strongly transverse ; terminal joint moderately large. Head quite narrow, 
rather elongate and exserted, shining, with distant punctures. Thorax of rather 
peculiar form, owing to its being narrowed from the middle to the front, with the 
anterior angles greatly deflexed, the hind angles distinct, the surface rather coarsely 
punctate, without any basal impression. Llytra rather elongate, longer than the 
thorax, rather coarsely punctate, the punctuation closer at the base than towards the 
hind margin. Hind body rather slender, shining black; segments two to five each 
