114 IOWA STUDIES IN NATURAL HISTORY 
This form bears some resemblance to Euschistus tristigmus 
but aside from its much smaller size it may be told at once from 
that form by the absence of black spots on the venter and the 
fact that the ostiolar opening is continued in a long wrinkle. 
As Uhler suggests (l. c.), it ‘‘forms a connecting link between 
the Asopinae and the group represented by the genus Euschis- 
iuss- 
Although this is the most abundant and widely distributed 
member of the genus it is seldom met with in Iowa. Osborn 
recorded the species as ‘‘Quite rare’’ in the state and gave one 
locality record, Ames. But three Iowa specimens are at hand. 
A male from Solon was collected August 15; and two females 
from Robinson were taken August 17 on hazel (Corylus ameri- 
cana Walt.). The species has also been found on hickory (Carya 
sp.), and oak (Quercus sp.). While it is found practically 
throughout the United States it apparently reaches its maximum 
of abundance in the western states; curiously enough it has not 
been listed from Nebraska. 
Subfamily ASOPINAE (Spinola) 
This is a rather well marked subfamily reaching its maximum 
of development in regard to both size and coloration in the Neo- 
tropical region. Forty-three forms are recorded from America 
north of Mexico and ten of these are represented in the lowa 
fauna. Many of the members of the group are entirely or 
almost entirely predatory in habits and afford one of the nat- 
ural checks upon the undue increase of noxious species of in- 
sects, so that the group as a whole is of considerable economic 
importance. Following are the principal characters of the sub- 
family: 
Rostrum long, very thick, surpassing midcoxae; basal segment usually 
thickest; second segment longer than third. Bucculae very short, united 
posteriorly, covering only base of first segment of rostrum. Antennae of 
five segments, the basal segment very short, not reaching beyond anterior 
margin of head. Anterior tibiae with a small spine on inner surface. 
Ostiolar canal generally in the form of a long, more or less curved groove 
with sharply defined margins. 
Key to the genera 
Anterior femora armed with a spine or blunt tubercle near apex 
Scutellum large, broad, extending almost or quite to tip of 
