PLATE XXXII. 
Fie. 1. Ambrysus melanopterus Stal. The genital segment from a specimen in the 
Snow collection determined by Van Duzee. Yhe segment is more elongate than A. 
signorett and the claspers more slender and truncate at tip. Another character in this 
group that may have possibilities is a chitinized flap that is present on the margin of one 
of latter abdominal tergites. Its position is on the right side in the material of the two 
species examined and distinctly different in shape. 
Fic. 2. Saldid. The exposed genital segment of a species common in Kansas. Note 
the shape of the claspers and the tip of the genital segment as compared with Pentacora 
signoreti Guer., fig. 6. , si 
Fic. 3. Ambrysus signoreti Stal. The genital segment from a specimen in the Snow 
collection determined by Van Duzee. The segment is plump and the claspers broad. The 
drawing is partly free hand and from dorsal view. This bug was taken by Doetor 
Snow at San Barnardino Ranch, Arizona (Cochise county). 
Fig. 4. Notonecta mexicana. The male genital capsule of this species is much larger 
in proportion to the size of the insect than any other member of the genus examined. It 
differs from the others in having the cephalic end larger than the caudal end and in 
having a greatly developed lobe before the clasper. The drawing is to about the same 
scale as those on plate 1, and the insect about the size of N. insulata and N. irrorata, the 
genitalia of which are shown on figures 9 and 7 of plate XXXI. 
Fig. 5. Gelastocoris variegatus (Guer.). The specimen from which this drawing 
was made bears Uhler’s determination and was loaned for study by Mr. E. H. Gibson, 
custodian of the Hemiptera in the National Museum at Washington. The drawing is 
made from a ventral view of the bulb. In this genus the genital segment is asymmetrical, 
the right clasper (R. C.) being much more developed than the left (LL. C.) and armed 
with short peg-like processes. The segment has revolved a quarter turn to the right so 
that the tips of the claspers are directed to the right instead of dorsally. The general 
features of the genital armature are the same for all, but the western and eastern forms 
fall into two distinct groups as regards the shape of the right clasper. The right clasper 
(R. C., see figure) is produced on its caudal margin into a flat plate which bears a 
curved more or less finger-like process. The distal angle (a) which this plate forms with 
the shaft of the clasper is acute in all the western material and obtuse and sloping in all 
the eastern material examined. In Kansas we have both-forms. A series from western 
Kansas (Pawnee county) compare closely with this Uhler specimen. As a whole, they are 
pebbled and colored like the sand of the river flats upon which they live. A few speci- 
mens are more obscurely marked. There is no perceptible difference in the male genitalia 
of the whole series, however. In the Snow collections under G. oculatus there are speci- 
mens from Bill Wins Ford, Arizona, taken by Doctor Snow. Some are distinctly mottled 
and others more obscurely marked. The crenations and angles of pronotal margins are 
as in the G. variegatus (Guer.), determined by Uhler. The right clasper is acute angled, 
also. They are certainly the same as Uhler’s G. variegatus (Guer.). 
Fic. 6. Pentacora signoreti. The genital segment of a species common in the western 
portion of Kansas. Determined material by Van Duzee. The two species are here shown 
to suggest that a study of these parts should be made in making a study of the family. 
They may have some taxonomic value. 
Fig. 7. Gelastocoris oculatus (Fabr.). The specimens of the material from eastern 
Kansas, Tennessee, etc., as a whole, are less variegated in color pattern and from Mr. 
J. R. de la Torre Bueno’s notes (in litt.) are probably G. oculatus (Fabr.). These all 
agree in having the obtuse and sloping angled right clasper. Kansas is splendidly sit- 
uated for a study of geographical convergence. Western forms and eastern forms meet 
and Upper Austral and Lower Austral life zones are present. Dr. C. H. Kennedy’s study 
of the dragon flies has directed attention to this interesting feature. One of our graduate 
students is now engaged in working over the distribution of the toad bugs with this 
point in mind. A study of a wide range of material of each form will always be essential 
to the establishment of the range of variation in the species, and any character which is 
specifically discontinuous and unique to a species is always a welcome discovery. 
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