48 IOWA STUDIES IN NATURAL HISTORY 
of America have the best representation with the Australasian 
region showing the smallest proportionate number. Consider- 
able variation in size, form and coloration as well as in food 
habits obtains in the family which, in North America, is readily 
separable into three distinct subfamilies and totals about two 
hundred forms; forty-seven forms are herewith recorded for 
Towa. Following are the chief diagnostic characters: 
Scutellum usually moderate in size and more or less narrowed towards 
apex; in a few cases the scutellum covers most of the abdomen and under 
these circumstances the colors are sharply contrasted or else a prominent 
tooth is present just anterior to the lateral angles of the pronotum. Pri- 
mary and subtended veins of wing contiguous or subcontiguous, diverging 
apically; hamus not present. Veins of membrane arising near the interior 
basal angle or springing from a vein which begins at this angle and runs 
parallel to the margin of the corium; corium obtuse at apex. Basal seg- 
ment of venter very distinct, at least towards sides. Connexivum of ab- 
domen with seven visible dorsal segments. Tibiae rarely strongly spinose, 
often unarmed. Tarsi 2- or 3-segmented. 
Key to the subfamilies 
Buceulae long, parallel or subparallel; rostrum inserted 
a little behind tip of tylus; basal segment of rostrum 
usually slender and largely embedded between bucculae 
Scutellum almost covering abdomen, broad at tip; 
frena very short; pronotum with a single prominent 
tooth anterior to lateral angles........ GRAPHOSOMATINAE 
Seutellum smaller, more or less narrowed at apex; 
frena longer; pronotum either without teeth or with 
numerous teeth near antero-lateral angles... PENTATOMINAE 
Bucculae small and converging posteriorly under ros- 
trum; rostrum inserted near tip of tylus; basal segment 
of rostrum: short and thick: 7.) 2.0 24) 922 ee eee ASOPINAE 
Subfamily GRAPHOSOMATINAE (Jakovlev) 
But three genera of this rather distinct subfamily which is 
mainly Palaearctic and continental in distribution are found in 
North America. The North American forms are all small, dark 
colored and of a roughened appearance. Two species of the sub- 
family are here recorded for Iowa. 
Head long, lateral margins sinuate; juga broad at apex, equalling or 
exceeding tylus; eyes prominent and stylated. Pronotum with anterior 
angles produced into a tooth or lobe; humeral angles emarginate and with 
