June, 1908.] 
Guatemalan Hemiptera. 
37i 
To make any comment on Dr. Bergroth’s finished work “were 
to paint the lily,” nevertheless a few T remarks for greater clear¬ 
ness may not be out of place. The paper in question, while based 
on some of the Guatemalan material does not cover all the speci¬ 
mens, nor give all the records, since only a few of the Trepobates 
were sent, with others from Arizona. The other localities will 
appear in the systematic part of the list. 
In reference to Rheumatobates , the brush at the inner end of 
the fore tibia is also to be found in other Gerridae and its use 
appears to be for cleaning the antennae at least, an operation 
repeatedly observed by me in Microvelia americana Uhler. 
While their apparently preferred habitat is in running waters, 
in my experience Rh. rileyi appears to prefer coves and slack 
waters along the banks of the streams it frequents. Neverthe¬ 
less, I have found it abundant in a lake in New Jersey, in places 
where there was no current, so it would appear to me that it is 
not altogether impossible to breed them. Dr. Bergroth also 
very fully described the winged form of Rh. tenuipes Meinert, of 
which and also of rileyi, 1 possess specimens. But I have 
also taken a brachypterous form in this latitude, in which the 
hemelytra do not reach the end of the abdomen, being appar¬ 
ently truncate. In some subsequent paper, I hope to be able 
to more fully elucidate these points. 
FAMILY GERRIDAE. SUBFAMILY HALOBATINAE. 
E. Bergroth. 
To this subfamily I refer only the genera having the inner 
margin of the eyes convexly rounded. In the subfamily Gerrinae 
the ocular orbita is arcuately sinuate behind the middle. Mayr 
(Reise d. Novara, Hem., p. 169) was the first who based the 
primary subdivision of the Gerridae on this character. But 
little attention has been paid to it by Bianchi and Champion, and 
none at all by Distant in his Fauna of British India, but it is 
carefully indicated in Kirkaldy’s generic descriptions. As char¬ 
acter for the two subfamilies Bianchi solely gave (in which he was 
followed by Distant) the breadth of the body compared to its 
length, a feature entirely unsatisfactory as justly observed by 
Champion who does not accept the subfamilies. Of the genera 
included in the Halobatinae by Bianchi at least one— Pota- 
mometra Bianchi—-really belongs to the Gerrinae. I may be mis¬ 
taken, but I believe that the character derived from the form of 
the eyes, slight as it may seem, is indicative of a real affinity 
between the genera having these organs similarly built and I 
also believe that this rather trivial character could be supported 
by others when these polymorphous, as yet little known and little 
understood insects have undergone a thorough and much needed 
