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RESTHENIA. 255 
aa. Basal joint of the antenne about equal in length to that of the 
head, or very little longer or -shorter. 
17. Resthenia mimica, n. sp. 
Black ; anterior half of pronotum, which is also centrally and posteriorly continued in a wedge-shaped streak 
into the black basal area, scutellum, base of corium to about middle of scutellum, and sternum bright 
yellow. 
The second joint of the antenne is somewhat distinctly incrassated in its apical half, and is distinctly pilose ; 
tibise thickly and rather longly pilose. 
Long. 11 millim. 
Hab. Panama, Bugaba (Champion). 
A single example of this interesting species was obtained by Mr. Champion. It 
closely resembles in colour and markings a species belonging to another section of the 
genus (f. ornaticollis, Tab. XXII. fig. 5), from which it differs by the shorter basal 
joint of the antenne. . mimica is also a larger insect than . ornaticollis, and the 
markings of the pronotum are also different. 
18. Resthenia guatemalana, n. sp. (Tab. XXV. fig. 5.) 
Head brownish ochraceous, with a central linear spot at apex, the eyes and antenne dark fuscous; pronotum, . 
scutellum, and base of corium to about centre of scutellum pale stramineous; pronotum with two con- 
tiguous transversely elongate dark fuscous spots near anterior margin ; corium (excluding base), membrane, 
and legs fuscous. Body beneath, with the head, sternum, and coxe stramineous; the abdomen fuscous, 
with the margins of the segmental incisures stramineous. 
Long. 83 millim. 
Hab. GuateMALA, Aceituno (Champion). 
This, like the last species, is represented (at present) by a single example, and closely 
resembles in general pattern above a species in another division of the genus (R. chiri- 
guina, Tab. XXV. fig. 3), from which it structurally differs in the length of the basal — 
joint of the antenne. &. guatemalana is also a paler-coloured insect than &. chiriquina 
and the scutellal and sternal markings are different in the two species. 
This superficial resemblance of two species belonging to different sections of the same 
genus, and thus structurally differentiated in what is best but inadequately described as 
in a subgeneric manner, is not uncommon in other families of insects and notably in the 
Rhopalocera. In some cases this has caused the erection of a number of unnecessary and 
perplexing subdivisions styled genera, and has elsewhere been somewhat grandiloquently 
described as affording the material for a new “ philosophical extension of the theory of 
mimicry.” The factsseem to show a biological law of which we are at present in ignorance. 
19. Resthenia plena, n. sp. 
Dull sanguineous ; antenne, eyes, scutellum, corium, membrane, a large oblong spot at apex of abdomen, 
apices of femora, and the tibie and tarsi black. Rostrum reaching the intermediate coxe, its apex 
pitchy. 
Body somewhat ovate, and finely and obscurely pilose. 
Long. 8 millim. 
Hab. Muxtico (coll. Signoret). 
