128 
THE STUDY OF INSECTS . 
J. Head with a transverse incision in front of the 
ocelli, which are always present. (Fig. 175.) 
p. 143.BERYTIDiE. 
JJ. Head without transverse incision. 
K. Membrane with four or five simple veins 
arising from the base of the membrane; the 
two inner ones sometimes joined to a cell near 
the base. (Fig. 146.) p. 142. Lyg^id^e. 
KK. Membrane with many, usually forked 
veins, springing from a transverse basal vein. 
(Fig. I47.) p. 143 . COREIDiE. 
DD. Antennas five-jointed. 
E. Scutellum nearly flat, narrowed behind. 
F. Tibias unarmed or furnished with very short spines, 
p. 144 . Pentatomid.e. 
FF. Tibias armed with strong spines in rows. p. 145. 
CYDNIDiE. 
EE. Scutellum very convex, covering nearly the whole ab¬ 
domen. 
F. Lateral margins of the scutellum with a furrow in 
which the edge of the wing-cover fits when closed. 
p. 146. CORlMELiENID^E. 
FF. Lateral margins of the scutellum without a furrow, 
p. 146. SCUTELLERID/E. 
In the following pages we have discussed the families of the Hete- 
roptera in the order in which they are commonly arranged by writers 
on these insects. The aquatic families are placed first, the semi- 
aquatic next, and the terrestrial last. We do not believe, however, 
that this represents well the lines of development of these insects. It 
seems probable to us that some of the terrestrial forms, as the Penta- 
tomidae, resemble the ancient Heteroptera more closely than do the 
aquatic forms; and that the aquatic forms are really very highly spe¬ 
cialized and represent the summit of one of the lines of development. 
Perhaps the Scutelleridse represent the summit of another line. 
But as we have been unable to give the matter sufficiently thorough 
study to warrant our proposing a new arrangement, it seems best to 
follow the old one, merely indicating our belief in the necessity for a 
revision of the subord**i*. 
