9 6 THE STUDY OF INSECTS 



TABLE FOR DETERMINING THE FAMILIES OF THE HEMIPTERA 



A. Antennae shorter than the head, and nearly or quite concealed in a cavity beneath 

 the eyes. 



B. Hind tarsi with indistinct setiform claws (except in Plea, of the family No- 

 tonecitidae, which are less than 3 mm. in length). 

 C. Fore tarsi consisting of one segment, which is flattened or shovel-shaped, and 



without claws; head overlapping the prothorax dorsally. p. 97. . . .CORlxiDiE 

 CC. Fore tarsi of the usual form, and with two claws; head inserted in the 



prothorax. p. 98 Notonectid^e 



BB. Hind-tarsi with distinct claws. 



C. Caudal end of the abdomen furnished with a respiratory tube composed of a 

 pair of grooved, thread-like organs; tarsi one-segmented, p. 98. . . .Nepid.e 

 CC. Caudal end of abdomen without long respiratory tube. 



D. Legs flattened, fitted for swimming; caudal end of the abdomen furnished 

 with a pair of strap-like appendages (these appendages are retractile and 

 are frequently withdrawn from sight) ; tarsi two-segmented, p. 99 



BELOSTOMATID/E 



DD. Legs fitted for walking; abdomen without strap-like caudal appendages. 



E. Without ocelli, p. 107 Kaucorid/e 



EE. Ocelli present, p. 100 Gelastocorid/E 



AA. Antennae at least as long as the head, usually free, rarely (Phymatidce) fitting in 

 a groove under the lateral margin of the pronotum. 

 B. Body linear; head as long as the three thoracic segments, p. 107 



HYDROMETRID/E 



BB. Body of various forms, but, when linear, with the head shorter than the 



thorax. 



C. Last segment of the tarsi more or less split, and with the claws of at least 



the front tarsi inserted before the apex. 



D. Hind femora extending much beyond the apex of the abdomen; the 



middle and hind pairs of legs near together and very distant from the 



front pair; beak four-jointed, p. 101 Gerrid.e 



DD. Hind femora not extending much beyond the apex of the abdomen; 

 middle pair of legs about equidistant from front and hind pairs (except in 



Rhagovelia); beak three-jointed, p. 101 Veliid^e 



CC. Last segment of the tarsi entire, and with the claws inserted at the apex. 

 D. Antennae four-jointed.* 



E. Hemelytra resembling network, and very rarely with any distinction 



between the corium and the membrane, p. 104 Tingid/E 



EE. Hemelytra of various forms or absent, but not of the form presented 

 by the Tingidae. 



F. Beak three-jointed. 



G. Hemelytra when well developed with an embolium (Fig. 147); those 



forms in which the adult has vestigial hemelytra have no ocelli. 



H. Hemelytra vestigial; parasitic bugs preying on man, bats, and 



birds, p. 102 Cimicid.^ 



HH. Hemelytra usually well developed; not parasitic bugs. p. 102 



Anthocorid^e 



GG. Hemelytra when well developed without an embolium; those 

 forms in which the adult has vestigial hemelytra have ocelli. 

 H. Ocelli wanting. 



I. Body greatly flattened, p. 108 Aradid.e 



II. Body not greatly flattened, p. 103 Reduvud/E 



HH. Ocelli present, though sometimes difficult to see. 



I. Beak long, reaching to or beyond the intermediate coxae; an- 



tennae not whip-like; membrane of hemelytra with looped 

 veins, p. 100 . . Saldid/E 



II. Beak not reaching the intermediate coxae. 



J. Front legs with greatly thickened femora, p. 104. .PHSTMATHME 



JJ. Front femora somewhat thickened, but much less than half 



as wide as long. p. 103 Reduviid^e 



* In some cases there are minute intermediate joints between the principal joints 

 of the antennae; for the purposes of this table these intermediate joints are not counted. 



