
AQUATIC INSECTS OF FRESHWATER 

water. The eggs are remarkably large for the size 
of the insect. They are predaceous, feeding upon 
living prey from which they suck the juices. The 
most general species of the Eastern United States 
are Hydrometra lineata, Fig. 208, and Hygrotrechus 
remigis. 
Marsu-Treapvers belong to the family of 
Limnobatide and are very slender, almost thread- 
like insects rarely over % inch long, with long heads, 

. elongated thorax and abdomen, hairlike legs and of 
ists 208, Waterstrideror inconspicuous dark color.. They crawl over the 
ater, Hydrometra lineata, 
Enlarged. mud and the water surface or adhere to water plants 
partly above the surface, feeding upon the eggs and -- ee 
small larve of insects and snails. The most 
generally distributed species are Limnobates lineata, 
Fig. 209, and the allied Limnopus rufoscutellatus. 
Aguatic Priant-Lice belong to the family of 
Aphidide, commonly known as Aphides, small 
soft-bodied winged or wingless insects, with oval- 
lobed bodies, small heads, distinct eyes, filiform 
antennz and six legs; which when winged have two 
pairs of lace-like membranous wings. At the tip 
of the abdomen there are usually a pair of cauda or 
upward protruding air breathing tubes. They are 

- usually viviparous and feed upon juices by means of 
a three-jointed piercing and sucking beak inserted — FIG. 209. Marsh-treader, 
Limnobates lineata. 
into the tender portion of growing plants. The most Enlarged. 
general species of Aphides which the 
aquariist is likely to encounter is 
Khopalosiphus nymphee, Fig. 210, 
which infests the emersed and float- 
ing leaves of Sagittaria, Potamogeton, 
Duckweed, Cattails, Water-plantains, 
FIG. 210. Aquatic plant-louse, Rhopalosiphus nymphew, Water-poppies and Lilies; while the 
winged andiyinglesstages. | Enlarged. last two mentioned plants also have 
Siphonophora lili, and two greenhouse species, Aphis lilico’a and 
Rhopalosiphus dianthi. They produce a disfigurement of the leaves and 
cause decay by sapping the juices. 
Orper Nevuroprera. Of this order a considerable number of 
families are aquatic. All have the body elongated, thin and broad, net- 
veined membranous wings, large head with the mouth parts well developed, 

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