32 IOWA STUDIES IN NATURAL HISTORY 
the following subfamily. Twenty-seven species are at present 
recorded from North America; six of these have been taken in 
Iowa. The characters given in the foregoing table will suffice 
for ready diagnosis of this group. 
Key to genera 
Head with submarginal teeth 
Coria of hemelytra not contiguous posterior to scutellum; the 
latter broadly rounded at tip; ostiolar canal enlarged into a 
broad. lobe<at) tip 2.0 02.123 ee ee ee ee Cydnus (1) 
Coria of hemelytra contiguous posteriorly ; scutellum triangu- 
lar, convex; ostiolar canal long, linear ....... Amnestus (4) 
Head without submarginal teeth 
Pronotum with an impressed, sinuated, antero-marginal line; 
ostiolar canal fusiform, transversely incised next the tip 
Reg al ee remem PRE CECA AA tot nico & Pangaeus (2) 
Pronotum without impressed, sinuated, antero-marginal line; 
estiolar canal long, spatulate, rounded at the tip Geotomus (3) 
Genus CYDNUS Fabricius 
1803. Cypnus Fabricius (in part), Syst. Rhyng., 184. 
1851. AiruHus Dallas (in part), List Hem., 110 and 112. 
1876. Microporus Uhler, Bull. U. S. Geol. Geogr. Surv., II, no. 
5; 210. 
1877. Microporus Uhler, Bull. U. S. Geol. Geogr. Surv., III, 
373. 
General form broadly oval, polished, moderately convex, hairy. Head 
broadly rounded, the lateral submargins armed with stout teeth and fringed 
with long hairs; edges sharp, recurved; tylus shorter than lateral lobes. 
Rostrum reaching between mid-coxae. Pronotum obsoletely transversely 
impressed, the anterior angles bluntly rounded, the antero-lateral margins 
thickly fringed with long cilia; anterior margin deeply sinuated but without 
submarginal impressed line. Scutellum bluntly triangular, broadly 
rounded at tip, the apex a little depressed. Corium short, wide, the outer 
angle produced backwards. Odoriferous canal short, placed very near 
the sternum, the outer extremity expanded into a lobe-like pit. Outer mar- 
gins of venter compressed. Legs heavy, the anterior femora flattened and 
armed with acute spines on both outer and inner edges; anterior tibiae 
compressed and all the tibiae with heavy spines. 
Cydnus obliquus (Uhler) (Puate I, Figure 3, Puatse I], Figure 
3, and PLATE V, FIGURE 1) 
1872. Microporus obliquus Uhler, Rept. U. S. Geol. Surv., V, 394. 
