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March, 1913-] Barber : Aquatic Hemiptera. 29 

T. Carolina Linne. 

Bronxville, N. Y., V (Woodruff) ; Yaphank, N. Y., VII ; Wading 
River, N. Y., VIII ; Staten Island, IV, V, VI, VII, IX, X ; Newfound- 
land, N. J., IX; Great Notch, N. J., V; Jamesburg, N. J, IX; Lake- 
hurst, N. J., IV, 25, 1908, many individuals and a pair in copulation; 
VI, VIII. Only two or three of our dragonflies have as long a season 
as this, namely from April to October. We quote the following from 
the " Preliminary List of the Dragonflies of Staten Island with notes 
and Dates of Capture " (this Journal, Sept., 1898) : " On July 15, 
1894, a male Tramea Carolina was flying over one of the Four Corners 
iron mine ponds. Soon a female came and commenced dipping her 
abdomen into the water. In a moment she was seized by the male and 
they flew away. In a half hour they were back and went flying about 
together, the male now and then suddenly letting go his hold and with 
equal rapidity catching the female again by the neck. Other male 
dragonflies flew after them and when the female stopped to lay eggs, 
they annoyed her considerably. The chief among the disturbers was 
a Libellula basalis. After a time the male Tramea left his mate and 
she was quickly seized by the aforesaid Libellula basalis, after which 
they flew about together for a considerable time. After letting go his 
hold once and flying down the pond, the L. basalis returned and seized 
the Tramea a second time." 



AQUATIC HEMIPTERA. 

By H. G. Barber, 
Roselle Park, N. J. 

The aquatic Hemiptera have excellent and frequently wonderful 
adaptations to their environment, exhibiting among them most mar- 
velous variability of construction for their life in or on the water. 
The local, strictly aquatic species, belong to ten families of the hete- 
ropterous Hemiptera. These for convenience of treatment of relation 
of adaptations to habit may be grouped into (1) those which spend 
their active existence on the surface of the water, (2) those which 
habitually walk about upon some substratum beneath the water and 
(3) those which are, for the most part, free swimmers. 



30 Journal New York Entomological Society. t VoL XXI - 

In all of these the most striking adaptations of structure are con- 
nected with habits of locomotion, breathing and feeding, which are 
variously modified to suit the particular environment referred to 
above. With few exceptions these are all carnivorous and are 
equipped with the short stout beaks necessary for piercing the tissues 
and sucking the juices of animals. Correlated with this, the great 
majority have the fore legs modified for seizing and holding the prey. 

Although a few forms in the west have been recorded as occurring 
in water strongly impregnated with various mineral salts, and a few of 
our local forms in brackish water, they are for the most part strictly 
fresh water forms. The species likely to occur in any body of water is 
determined somewhat by the character of the water, the nature of the 
current and the presence or absence of accumulated plant life. Some 
species preferring the swift moving stream in which they seem to love 
to sport against the force of the current ; others, and perhaps the 
greatest number, are found only in still waters of ponds or the quiet 
waters of bayed out parts of streams where they sometimes congre- 
gate in immense numbers. 

Quite a number of these aquatic hemiptera, notably members of 
the families Belostomatidae, Corixidae and Notonectidae, have well- 
developed wings and readily migrate from one body of water to an- 
other and at such times, as has been frequently observed, are at- 
tracted to bright lights. The great majority of species, however, 
are fixed in their environment and though provided with wings are 
frequently incapable of flight. Others are dimorphic as to wings. 
In the Gerridse and allied families there occur a number of species 
in both the winged and unwinged state. 

The species which live actively upon the surface of the water 
belong to the following families, Gerridae, Veliadae, Hydrometridae, 
Neogeidae and Mesoveliadas. They have more or less elongated bodies 
and slender legs. The beautiful ease with which they glide and skip 
about over the surface of the water is due to the fine plush-like coating 
of hairs on the feet and ventral parts of the body by means of which 
they are enabled to enmesh a thin film of air which sustains their 
weight on the surface film and keeps the body dry. Unlike the mem- 
bers of the second and third groups the antennae are well developed 
and exposed. As they breathe surface air they have no peculiar 
method of respiration differing from terrestrial forms. Some of these 



March, 1913.] Barber : Aquatic Hemiptera. 31 

forms prefer the current of swiftly moving streams, but the majority 
find more congenial surroundings on the surface of quieter waters 
and a few may even make excursions upon land, where they may be 
found in damp situations. They are all carnivorous, using the fore 
legs for holding their prey, which usually consists of dead or living 
insects. They all hibernate, concealing themselves at the bottom of 
their retreat to reappear again on the surface early in the spring. 

The forms which walk about on submerged sticks or stem of plants 
beneath the water belong to the family Nepidae. The most striking 
modification they present is a long respiratory tube through which 
they may breathe surface air while the body is concealed beneath the 
water. Their legs are long and slender and the fore legs are strong 
and raptatorial for holding the prey. They more frequently occur 
in shallow, sluggish streams or ponds well supplied with plant life. 
Only three species are likely to occur in this vicinity belonging to the 
genus Nepa and Ranatra. 

The free swimming forms are more abundant, locally, than in the 
two preceding groups. They usually have the hind pair of legs either 
broadened or fringed with long hairs to resist the water and serve as a 
swimming organ. Here are included the families Corixidae, Belo- 
stomatidae, Naucoridae and Notonectidae — a group of carnivorous 
forms, with the possible exception of Plea striola, having the custom- 
ary short, stout beak. Some of these species are of economic impor- 
tance as they frequently attack young fish or destroy their eggs. 

The Corixidae, or water boatmen, are the most numerous in species 
The hind legs are fringed with long hairs and their fore legs are pe- 
culiarly modified, bearing characters which are largely used in their 
specific differentiation. Carrying a supply of air beneath the elytra, 
they may remain submerged for an indefinite period. 

The Belostomatidae include some of the largest hemiptera known. 
The second and third pairs of legs are broad and paddle like and 
fringed with long hairs. The fore legs are developed into strong 
clasping organs. They are good swimmers and strong fliers, fre- 
quently attracted to light several miles from their breeding places. 

The Notonectidae, or back swimmers, have the not much broadened 
swimming hind tibiae fringed with hair and the modified clasping fore- 
legs. The ventral surface is provided with a mass of long hairs which 
enmeshes a supply of air for use beneath the surface. The species 



32 Journal New York Entomological Society. [Vol. xxi. 

differ considerably among themselves as to the quality of water they 
may select for their abode; Notonecta undulata, for instance, may 
occur in the foulest kind of pools, while others must have compara- 
tively clean water. 

The family Naucoridae includes some broad, ovate forms which 
seem to prefer waters well stocked with vegetable matter. They have 
the usual talon-like fore legs, but as their hind legs are neither broad- 
ened nor fringed with hair, they are poor swimmers, depending more 
upon walking about upon the submerged plants. 

Of all of the Heteroptera perhaps the aquatic species have been 
less well and accurately known to American entomologists than any 
other group. This has been due to the fact that because of their 
wide distribution, ease of collecting, and generally larger size they 
received the attention of earlier systematists, who were satisfied to 
give them but a brief and not distinctive characterization to make 
them recognizable without an examination of the types. These types, 
for the most part, having either been destroyed or deposited in mu- 
seums abroad systematists have depended upon the meager descrip- 
tions at hand, with the result that there has arisen considerable con- 
fusion and uncertainty in fixing certain species. Especially is this so 
in the family Corixidae. 



AQUATIC COLEOPTERA. 

By Chas. W. Leng, 
West New Brighton, N. Y. 

Few, if any, beetles are aquatic throughout all the stages of their 
existence; even those commonly called water beetles pupate on land 
and sometimes at least lay their eggs on leaves out of the water. The 
beetles which are more or less aquatic in habit include the several 
families of water beetles, the Parnidae and Elmidae, the tribe Dona- 
ciini in Chrysomelidae, some tribes of snout beetles and a few other 
smaller families. All of these exhibit some modifications of struc- 
ture and vestiture in harmony with their aquatic life, modifications 
that are on the whole more marked in the adults than in the larvae, 
especially in the case of the plant-infesting species ; all exhibit a more