180 
Hind tibiae sulcate above, at least on basal half. 
Pronotal hind angles emarginate (Iowa, Col. to Vancouver and 
LOWER’. Cal>,\ IMG: I. 5 oct svete tatelavenevelers scetanel sia etaics ars, iefotniats 16. Prionosoma. 
Pronotal hind angles not emarginate. 
Bucculae sloping off at posterior end, without evident posterior 
lobe. 
Margins of pronotum arcuate and explanate; membrane veins 
anastomosing {siete en sis sietcasiaress, wise te dente wipe cree 17. Menecles. 
Margins of pronotum sinuate; veins of membrane not anas- 
tomosing. XN 
Frena reaching well beyond mid-scutellum. 
Pronotal margin serrate anteriorly......... 18. Huschistus. 
Pronotal margin entire (Fla.)............... Padaeus Stal. 
Frena not reaching beyond mid-scutellum; pronotal margin 
entire (Kan. to Cal., north to Vancouver. .EHysarcoris Hahn. 
Bucculae elevated at posterior end into a distinct lobe, ending 
abruptly behind. 
Tylus not more prominent above than juga, which converge 
over it at apex (Col. to Cal., and N. Dak.) ....Carpocoris Kol. 
Tylus throughout more prominent than juga, which are 
parallel. 
Distal part of scutellum narrower than elytra.............. 
Trae Se cate, torah mate lsloras ol Gun Frans ie etamatane eaten ane ois 19. Hymenarcys. 
Distal part of scutellum broader than elytra...... 20. Coenus. 
[It was the intention of the author to arrange his keys according to 
’ the natural sequence of the genera, but evidently the attaching of impor- 
tance to certain characters led him to place between closely related genera 
one or more genera that are apparently not closely related to the genera 
which they separate. An example may be seen in the case of Dendro- 
coris, since the genera Thyanta and Banasa are undoubtedly very closely 
related while Dendrocoris, intervening, is readily separable from them by 
a number of striking anatomical characters which are in my opinion of 
paramount importance in this family. The male genitalia are very dis- 
tinctive in all the species of Dendrocoris which I have seen, the deep 
central excavation and lateral clawlike processes (Pl. XVIII, Fig. 28) 
being strikingly different from the ordinary forms in Thyanta and its 
allies (Pl. XX, Fig. 70, 72, 75, 77). The genitalia of the females differ 
from those of Thyanta and allied genera in having the basal paired plates 
entirely covered by the apical ventral segment when in their normal posi- 
tion. In addition to the genital differences mentioned the metasternum 
of Dendrocoris lacks the central ridge except in some cases at its anterior 
extremity. The male of this genus frequently has no protuberance on the 
second abdominal sternite, but the above characters will identify such 
specimens. ] 
[The arrangement of the genera of Pentatominae and other sub- 
families of Pentatomidae has apparently been rather arbitrary if one may 
judge from the repeated re-alignment of the constituent genera in various 
