SCUTELLEROIDEA OF IOWA 31 
hardy than 7. ater but this deficit is made up by its extreme 
prolificacy. 
Subfamily CYDNINAE (Dallas) 
This subfamily of the Scutelleroidea contains the so-called 
‘‘eround bugs’’ which are, as a group, quite readily distinguish- 
able from others of the superfamily, but some of the species are 
separated from one another with more or less difficulty. Some of 
this difficulty has recently been obviated through the studies of 
Van Duzee who has relegated certain of Uhler’s genera and 
species to synonymy so that the classification has been somewhat 
simplified. However, considerable variation obtains in punctu- 
ation, vestiture, etc., even among the individuals of a given 
species, thereby rendering difficult, in certain cases, satisfactory 
delimitation. | 
Most of the North American species, of which there are 
twenty-nine recorded are found only to the West and Southwest. 
All are more or less fossorial and live in sandy or semi-arid 
places. The principal characters of the subfamily are as fol- 
lows: 
Body generally oval, more or less orbicular or elliptical. Colors piceous 
or black. Head clypeate or semicircular. Antennae of five segments (us- 
ually) and inserted under the flat margins of the sides of the head. Second 
segment of rostrum usually compressed. Scutellum broad and bluntly 
rounded or triangular, shorter than corium and with apex depressed. Apex 
of corium rather broad. Generally fossorial species; tibiae beset with stout 
spines and usually, in addition, numerous long hairs. 
: Key to the tribes 
Femora compressed ; tibiae closely set with stout spines; anterior 
tibiae more or less compressed; tarsi slender, filiform; antennae 
mcpalive OF tye SCOMeENtS oe ve eee Se eo Oe CYDNINI 
Femora, except anterior pair, cylindrical, sub-fusiform; tibial 
spines fewer and shorter; anterior tibiae not compressed; tarsi 
stout, second segment more slender than basal segment; an- 
feumae usually of five Sepments: ... 0.25... ee. SEHIRINI 
Tribe CypNINI (Stal) 
This tribe contains those species of the subfamily which are 
highly fossorial and the modifications correlated with such 
habits make them readily separable from our representatives in 
