1 IS 
MICROPOS. By L. B. Prout. 
flaveolata. 
super gressa. 
involuta. 
superba. 
planilimba- 
ta. 
laeta. 
ops. 
bogotensis. 
mamillifera. 
intercepta. 
were mixed with some totally unrelated (but mimetic) Dioptidae. The structure (head, y hindlegs and venation) 
are so essentially Sterrliine that one can only suppose that they have been superficially modified by their pro¬ 
tective needs. It is not, however, at all certain that all the genera represent a single stirps; there are some 
extraordinary and strongly divergent developments of the <$ genitalia which will perhaps materially modify 
our future systems of classification. Xanthyris, with shortened cells, 2nd subcostal of hindwing not stalked 
with 1st radial, and distinctive shape and pattern, is somewhat widely removed from the rest. antenna with 
fascicles of cilia, hindtibia very strongly tufted, tarsus very short; hindtibia of $ with 4 spurs. Areole ample, 
undivided. Genitalia (<$) with uncus bifid, much as in some Semaeopus, and the 8th segment with a “pseudo- 
mappa” (a “special modification of the 8th sternite”, see Supp.-Vol. 4, p. 23); a modified gnathos is present, 
as also in other genera of the group. The few species are all closely related. 
X. flaveolata L. (11 a). One of the first discovered and best known of the South American Geometridae. 
A detailed description is quite superfluous. Distributed from Costa Rica to Peru, French Guiana and S. E. 
Brazil. 
X. supergressa Bastelb. (17 a) differs in the broader borders, that of the hindwing nearly one-half the 
wing-length, and in their less dentate proximal edge (on the hindwing almost simple). The patagium lacks 
the yellow dot or spot which is almost invariably present in flaveolata. The genitalia show differences in the 
aedoeagus, the gnathos and the costal armature of the valve. Colombia (type from El Credo) and W. Ecuador. 
X. involuta Bastelb. (17 a). I have not been able to study this in detail, but suppose it to be another 
good species, as flaveolata varies so little; borders less uniform in width, narrowest at hindmargin, swelling 
strongly at costa, especially on the forewing. Pebas, Peruvian Amazons. 
X. superba Druce (17 a). Distinguished by the smooth proximal edge of its black borders, which are 
much narrower than those of sibpergressa; patagia as in flaveolata. Described from Cuzco, the same form known 
from La Paz, Bolivia. — planilimbata Warr ., from Chanchamayo (loc. tvp.) and the Peruvian Amazons, is 
somewhat more deeply coloured and has the black markings ampler than in typical superba , deeper black than 
in supergressa and without paler veins. 
20. Genus: Hfcropos Hbn. 
Palpus moderate, 2nd joint relatively long and strong. Antenna in both sexes bipectinate. Hind- 
tibia of $ broad, very short, with a single terminal spur; of $ with 1 median and 2 terminal spurs. Abdomen 
in strongly (sometimes excessively) elongate. Forewing, at least in the longer and narrower than in most 
of the group; cell over L>; areole double. Hindwing with 2nd subcostal stalked. Type, M. longalis Hbn. A 
very natural genus except as regards laeta and its immediate offshoots, which are placed here chiefly on account 
of the 3-spurred $ hindtibia. 
A. Antenna of $ simple; abdomen o f $ not elongate. 
M. laeta Walk. ( = pseudisis Bsd., isis Warr., nec Hbn.) (17 c). Pectinations of B rather short, termin¬ 
ating in tufts of cilia. Genitalia of more Cosymbia- like in the valves, while those of typical Micropos have 
quite simple, undivided valves. Apart from the structure, the typical form is easily distinguished from similarly- 
marked species in the succeeding genera by the bent transverse band of the forewing, which turns outward 
towards termen instead of continuing to run towards tornus; colour generally of a slightly deeper orange. 
Mexico (loc. typ.) to Colombia and Venezuela; its occurrence in Surinam is doubtful. ops Druce (17 c), 
almost confined to Bogota and adjacent localities, is very distinct in the much reduced black markings; the 
transverse band is never complete; in the typical form it is reduced to attenuated vestiges at each end, but 
transitions also occur. bogotensis Dogn., also from Bogota (La Union, 1 $), is probably an extreme aberration 
of ops, with the borders further attenuated (the terminal of the forewing posteriorly and of the hindwing in 
large part only about 1 mm wide), the costal black of the forewing ceasing at the end of the cell, the trans¬ 
verse band only slenderly represented by some black scales on the discocellulars. I have an almost equally 
extreme $ from Upper Rio Negro, E. Colombia, collected with normal ops rfrf. 
M. mamillifera Warr. May also well be a form of laeta (17 c); structure the same. Borders not, as in 
ops, narrowed; costal projection (incomplete transverse band) large, “mamillate”, behind the 1st median vein 
rounded, instead of tapering to a point as in ops. C'achabe, Ecuador, low country, 1 
M. intercepta Walk. (= antholia Walk., adunca Bsd.) (17 c) was made the type of a genus Scaptia 
Walk., but quite agrees in structure with typical Micropus, though one “sport", out of numerous $$ examined, 
has lost the proximal spur from both hindlegs. Distinguished by its narrow longitudinal streak; the distal 
one always ample, flattened anteriorly. Mexico to Nicaragua, Walker’s types respectively from Nicaragua 
