522 HEMIPTERA. 



In Aphis the seven-jointed antennae are longer than the body, 

 the two basal joints short and thick, the seventh the longest, 

 and near the end of the abdomen there are two long honey 

 tubes. Aphis avenoe Fabr. is abundant and verj' injurious to 

 the ears of wheat, sucking out the sap and greatly reducing the 

 bulk of the corn. In certain years it has spread over the 

 country in immense luunbers. Aphis mali Fabr. (Fig. 518, 

 winged female; Fig. 519, asexual female), and A. maHfolitx. 

 Fitch are found on the apple ; A. cerasi Fabr. on the cherry ; 

 A. p>G^'sicoi Sulzer on the peach, and A. brassicm Linn, on the 

 cabbage. There are about thirty species known in this 

 country. 



In Lachnus the sixth joint of the antennae is shorter than 

 the seventh, and the honey tubes are very short. Lachnvs 

 strobi is found on the white pine bushes often in great numbers. 

 Lachnus caryai Harris is a very large species 

 Avhieh lives on the Hickory. Mr. Walsh states 

 tliat he has "noticed in the autumu, numerous 

 apterous females on the same tree, which lived 

 many days and laid their eggs in confiuemeut, 

 but died without assuming wings." The genus Eriosoma differs 

 in having no honey tubes, and in having only two median (dis- 

 coidal) cells. The species are covered with a woolly Uocculent 

 substance, secreted from the abdomen, though no special 

 glands for this purpose have yd been discovered, while but lit- 

 tle '"honey" is exuded from the orifices of the aborted honey- 

 tubes. Eriosoma Icmigera Ilausmann, the Apple-blight, is 

 black, with the abdomen honey yellow. The eggs are laid in 

 the axils of the branches, especial^ near the roots of the tree, 

 if there are any suckers present, and are enveloped in the pow- 

 dery substance of the abdomen of the female. By their stings 

 in the bark numerous warts and excresences are produced, 

 the leaves turn yellow and drop ofi\ and the tree often dies. 

 Professor Verrill has found, about the middle of October, 

 among the wingless individuals, " a large number of both males 

 and females having well formed and ratlier large wings, but in 

 other respects closely resembling the rest." 



The genus Adelges was proposed by Vallot for certain broad, 

 flattened plant-lice, which attack coniferous trees, often raising 



