20 RHOPALOCERA. 
specimens confirming his statement. We found this species usually associated with 
M. doryssus in Guatemala, near Duefias (alt. 5000 ft.); both were very common in 
open woods, where they might be seen nearly the whole day flying a few feet from the 
ground. 
Our figures and descriptions are taken from typical specimens; the male was captured 
at Choacus in the valley of the Motagua, the female in the valley of the Polochic. 
2. Mechanitis isthmia. (MV. isthmicus, Tab. I. figg. 11, 12.) 
Mechanitis isthmia, Bates, P. Z. S. 1868, t. 29. f. 1°; Butl. & Druce, P. Z. S. 1874, p. 334? 
(partim). 
Sexus paulo dissimiles quoad fasciam posticarum longitudinalem nigram; alis anticis nigris macula basali 
fulva, fascia interna flava fere obsoleta; posticis fulvis fascia longitudinali nigra in mare bene distincta, 
in femina obsoleta aut omnino absente, posticarum margine anguste nigro. 
Hab. Costa Rica (Van Patten)?, Irazu, Caché (ZH. Rogers); Panama, Chiriqui, 
Calobre (Arcé), Line of railway (M‘Leannan)!. 
In some specimens of this race the yellow spot at the end of the cell of the primaries 
is absent ; in others it is ill defined; and in a few it is distinctly shown. The black 
longitudinal band on the secondaries of the females varies much, in some examples 
appearing as an incipient band at the apical angle; in others it is wanting altogether. 
This race is very abundant throughout the State of Panama, where its characters are 
fairly constant. In Costa Rica individuals are not wanting agreeing accurately with 
Panama specimens ; with these, however, are a larger proportion of examples which 
vary in the direction of the more northern race, MW. lycidice. From Guatemala we 
have a female specimen which has the dark primaries so characteristic of JZ. isthmia; 
but the secondaries have a well-defined longitudinal band, as in many examples of 
M. lycidice. ‘This is one selected from hundreds of the Guatemalan form, to which 
undoubtedly it must be considered to belong ; it shows, however, a tendency to assume 
the colour-pattern of a race geographically far removed from it, and proves that, though 
races are fairly constant in their respective areas, they are by no means absolutely so. 
Our figures and descriptions are taken from Panama specimens, whence the types 
were procured. | 
A form, closely allied to M. tsthmia, was described by Mr. Reakirt in 1865 as I. 
californica, from specimens sent him from Los Angeles in California (Proc. Ent. Soc. 
Phil. v. p. 223). The appearance of Mechanitis so far north is remarkable; and a con- 
firmation of its presence in California would be acceptable, as the record of the 
occurrence of another Panama species, [thomia panamensis, in the same paper, prompts 
the suggestion that some mistake may have been made in the locality assigned to 
them. 
