gg. Ocelli wanting; antennae more or less hidden in a groove.
h. Anterior c.o.xae inserted at or near anterior margin of the prosternum; front legs raptorial; beak three-segmented BELOSTOMIDae (with swimming legs), NEPIDae, NAUCORIDae.
i. Metasternum without a median longitudinal keel; antennae always four-segmented.
j. Beak short, robust, conical; the hairy fleck on the corium elongate, large, lying in the middle between the inner angle of the membrane and the outer vein parallel to the membrane margin; membrane margin S-shaped.
k. The thick fore femur with a relatively deep longitudinal furrow to receive the tibia.
Several American species (fig. 19f.). BELOSTOMA (= Lethocerus Mayer)
kk. The less thickened fore femur without such a furrow. B. GRISEUS. BENACUS Stal.
jj. Beak slender, cylindrical; the hairy spot on the corium rounded lying next to the inner angle of the membrane.
k. Membrane large, furrow of the embolium broadened.
_Z. aurantiac.u.m_, _fluminea_, etc. _Zaitha_
kk. Membrane very short; furrow of embolium not broadened. Western genus. _Pedinocoris_
ii. Metasternum with a long median longitudinal keel.
Southwestern forms. _Abedus ovatus_ and _Deniostoma dilatato_
hh. Anterior c.o.xae inserted at the posterior margin of the prosternum; legs natatorial. Back swimmers (fig. 19 b.).
NOTONECTIDae
i. Apices of the hemelytra entire; the three pairs of legs similar in shape; beak three-segmented; abdomen not keeled or hairy. _Plea_ Leach
ii. Apices of hemelytra notched; legs dissimilar; beak four-segmented; abdomen keeled and hairy.
j. Hemelytra usually much longer than the abdomen; fourth segment of the antenna longer than the third segment; hind tarsi with claws. _Bueno_ Kirk.
jj. Hemelytra but little longer than the abdomen; fourth segment of the antenna shorter than the third segment; hind tarsi without claws (fig. 19b).
NOTONECTA L.
ff. Antennae longer than the head; or if shorter, then the eyes and ocelli absent.
g. Eyes, ocelli, and scutellum wanting; beak three-segmented; head short; hemelytra always short; membrane wanting. Insects parasitic on bats. POLYCTENIDae
gg. Eyes present.
h. First two antennal segments very short, last two long, pilose, third thickened at the base; ocelli present, veins of the hemelytra forming cells. DIPSOCORIDae (= CERATOCOMBIDae) including SCHIZOPTERIDae.
hh. Third segment of the antenna not thickened at the base, second as long or longer than the third, rarely shorter.
i. Posterior c.o.xae hinged (cardinate), if rarely rotating, the cuneus is severed, the membrane is one or two-celled, and the meso- and metasternum are composite.
j. Ocelli absent, clypeus dilated toward the apex; hemelytra always short, membrane wanting. Species parasitic. Bed bugs, etc. CIMICIDae
k. Beak short, reaching to about the anterior c.o.xae; scutellum ac.u.minate at the apex; lateral margin of the elytra but little reflexed, apical margin more or less rounded; intermediate and posterior c.o.xae very remote.
l. Body covered with short hairs, only the sides of the p.r.o.notum and the hemelytra fringed with longer hairs; antennae with the third and fourth segments very much more slender than the first and second; p.r.o.notum with the anterior margin very _deeply sinuate_. CIMEX L.
m. Sides of the p.r.o.notum widely dilated, broader than the breadth of one eye, and densely fringed with backward curved hairs; apical margin of the hemelytra nearly straight, rounded toward the interior or exterior angles.
n. Body covered with very short hairs; second segment of the antenna shorter than the third; sides of the p.r.o.notum feebly reflexed, fringed with shorter hairs than the breadth of one eye; hemelytra with the commissural (inner) margin rounded and shorter than the scutellum, apical margin rounded towards the interior angle. The common bed bug (fig. 19h). C. LECTULARIUS Linn
nn. Body covered with longer hairs; second and third segments of the antenna of equal length; side of the p.r.o.notum narrowly, but distinctly, reflexed, fringed with longer hairs than the breadth of one eye; hemelytra with the commissural margin straight and longer than the scutellum, apical margin rounded towards the exterior angle. Species found on bats in various parts of the United States. _C.
pillosellus_ Hov.
mm. Sides of the p.r.o.notum neither dilated, nor reflexed, fringed with less dense and nearly straight hairs; hemelytra with the apical margin distinctly rounded. Parasitic on man, birds and bats. Occurs in the old world, Brazil and the West Indies. C. HEMIPTERUS Fabr. (= rotundatus)
ll. Body clothed with rather longer silky hairs; third and fourth segments of the antenna somewhat more slender than the first and second; anterior margin of the p.r.o.notum _very slightly sinuate_ or nearly straight in the middle, produced at the lateral angles. This is the species which in American collections is known as _C. hirundinis_, the latter being an old world form. It is found in swallows nests. O. VICARIUS. OECIACUS Stal
kk. Beak long, reaching to the posterior c.o.xae; scutellum rounded at the apex; lateral margins of the elytra strongly reflexed, apical margin slightly sinuate toward the middle; intermediate and posterior c.o.xae sub-contiguous. This species infests poultry in southwest United States and in Mexico. H. INODORUS. HaeMATOSIPHON Champ.
[Ill.u.s.tration: 160. Pselliopsis (Milyas) cinctus (2). After C. V.
Riley.]
jj. Ocelli present, if rarely absent in the female, then the tarsus has two segments; or if with three tarsal segments, the wing membrane with one or two cells.
k. Beak four-segmented, or with two-segmented tarsi.
ISOMETOPIDae, MICROPHYSIDae, and some CAPSIDae.
kk. Beak three-segmented.
l. Hemelytra with embolium; head horizontal, more or less conical; membrane with one to four veins, rarely wanting. ANTHOCORIDae
Several species of this family affecting man have been noted, ANTHOCORIS KINGI and CONGOLENSE, from Africa and LYCTOCORIS CAMPESTRIS from various parts of the world.
LYCTOCORIS FITCHII Reuter (fig. 19 j), later considered by Reuter as a variety of L.
CAMPESTRIS, occurs in the United States.
ll. Hemelytra without embolium. Superfamily ACANTHIOIDEA (= SALDae Fieber and LEPTOPODae Fieber)
ii. Posterior c.o.xae rotating.
j. Claws preapical; aquatic forms. GERRIDae and VELIADae
jj. Claws apical.
k. Prosternum without stridulatory sulcus (notch for beak).
l. Tarsus with three segments; membrane with two or three longitudinal cells from which veins radiate; rarely with free longitudinal veins (Arachnocoris) or veins nearly obsolete (Arbela); clavus and corium coriaceous; ocelli rarely absent. NABIDae
REDUVIOLUS (= CORISCUS) SUBCOLEOPTRATUS (fig. 19 g), a species belonging to this family, occurring in the United States, has been accused of biting man. This insect is flat, of a jet black color, bordered with yellow on the sides of the abdomen, and with yellowish legs. It is predaceous, feeding on other insects.
ll. With other combinations of characters.
HYDROMETRIDae, HENICOCEPHALIDae, NaeOGEIDae, MESOVELIADae, JOPPEICIDae
kk. Prosternum with stridulatory sulcus (notch for beak); with three segments, short, strong.