SUBFAMILY TRYXALINAE 23 
DICHROMORPHA Morse 
Vertex much shorter than broad, somewhat declivent, convex but 
more or less sulcate behind the distinctly elevated lateral carinae. 
These are straight or gently curved and meet at an angle, usually 
exceeding ninety degrees. The median carina is entirely wanting as 
are the lateral foveolae. The frontal costa is sulcate above and below 
the ocellus with the sides gently divergent downward and more or less 
constricted just below the ocellus and at the vertex. The face viewed 
laterally is nearly straight. The antennae are a little longer in the 
male but scarcely as long in the female as the head and pronotum. 
The disk of the pronotum is plain with the three carinae nearly straight 
and parallel, all cut distinctly behind the middle by the very faintly 
marked principal sulcus. The first and second sulci are not visible on 
the disk. The lateral lobes of the pronotum are perpendicular, longer 
than high, with the anterior and posterior margins strongly oblique, 
the latter plainly sinuate with the lower margin a little descending 
posteriorly, more strongly ascending and sinuate anteriorly. Lobes 
of the mesosternum are separated by a space broader than long in the 
female or as broad as long in the male; lobes of metasternum separated 
by a space as long as broad in the female or contiguous in the male. 
Tegmina are generally abortive, though rarely well developed; but in 
such cases the scapular area is not noticeably expanded. Posterior 
femora are stout and not banded; posterior tibiae are obscurely colored 
with the inner apical spurs very unequal. But one species, which is 
common throughout North America, is found here. 
Dichromorpha viridis Scudd. 
Dichromorpha viridis is dimorphic in both coloration and length 
of wings. The long-winged form (Chyrsochraon punctulatum Thom.) 
is rare but has been noted at Worthington. The short-winged form is 
very common and most of the males are green in color while the 
females are more commonly of grayish or brownish tints. It has 
appeared in the field that there may be some element of sexual attrac- 
tion attached to this diversity of coloration, since in numerous pairs 
observed in coitu the great majority were of oppositely colored indi- 
viduals. The species is commonly found in damp, shaded places, such 
as the rich vegetation of lowlands and low woodlands. It has been 
taken at Worthington, Pipestone, Amboy, Mankato, Redwood Falls, 
Monticello, and Fort Snelling. It has not been noted as yet north of 
the Minnesota Valley. 
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