CHIMASTRUM. 407 
It is only known to us as an inhabitant of our region from a single specimen taken 
by Herr Ribbe in Chiriqui, which was kindly submitted to us for examination by Dr. 
Staudinger. 
CHIMASTRUM, gen. nov. 
The primaries rounded, costa and outer margin outwardly convex, inner margin 
nearly straight. The subcostal nervure emits one branch before the end of the cell, 
and two afterwards; the upper radial joins the subcostal some way beyond the second 
branch and far beyond the end of the cell; the middle discocellular meets the subcostal 
at an acute angle, and is slightly curved and atrophied for most of its length ; the lower 
discocellular is also convex and atrophied for its upper half, it meets the median some 
way beyond the second branch; the costal and median sides of the cell are nearly 
equal ; the secondaries are rounded; there is a strong basal nervure; the upper disco- 
cellular meets the subcostal at an obtuse angle before the first branch, the lower 
discocellular the median at an acute angle some distance beyond the second branch ; 
the costal side of the cell is shorter than the median side. 
The front legs of the male have the trochanter inserted about the middle of the 
coxa; the femur =2 coxa and slightly dilated towards its distal end, tibia—coxa, 
tarsus=femur. The front leg of the female has the terminal tarsal joint a little 
longer than the second joint, and a setose pad beneath; the second, third, and fourth 
joints terminate beneath with a pair of spines. The palpi are peculiar in that the 
terminal joint seems to be fused with the middle joint—there is not even a constriction 
showing an atrophied joint; the basal joint is short. There are thirty-one joints in 
the antennz, whereof the terminal eleven form a well-defined club. 
The secondary sexual organs of the male have the harpagones with a single lobe, 
rather acute and setose towards its extremity; the penis is short, truncate, and 
decurved, and either within its cavity or attached to its sheath are two patches 
of long strong spines; the usual strap proceeds from its base to the base of the 
harpagones. 
In the female the bursa copulatrix has two short blunt granular spines, and the duct 
leading to it is much enlarged towards its external orifice ; it is corrugated towards the 
middle and granular. 
The alliances of this genus are somewhat complex. The neuration of the primaries 
differs essentially from that of Mesene in that the subcostal nervure emits one branch 
before and two after the ‘end of the cell, thus resembling to some extent Chemelimnas ; 
the position of the upper radial corresponds with neither genus. ‘The palpi are also 
peculiar, as are the male organs, though these bear some slight relationship in both 
sexes to those of Esthemopsis. We place the genus in this position solely in virtue 
of the neuration of its wings. 
