198 



ELEMENTARY ZOOLOGY 



striders (Hygrotrechus} can be easily kept in the laboratory aquaria- 

 and their swimming, breathing, and feeding habits observed. Note 

 especially the carrying of air down beneath the water. 



The Hemiptera are characterized particularly by their 

 highly specialized sucking mouth-parts, no other of the 

 sucking insects having the proboscis composed in the 



FIG. 62. The female red orange scale 

 insect, Aspidiotus aurantii, very injuri- 

 ous to orange-trees. It has no wings, 

 legs, nor eyes, but remains motionless 

 on a leaf, stem, or fruit, holding fast by 

 its long slender beak, through which it 

 sucks up the plant-sap. The male is 

 winged, and has no mouth-parts, taking 

 no food. (Photo-micrograph by Geo. 

 O. Mitchell.) 



FIG. 63. The female rose- 

 scale, Diaspis rosa, a 

 pest of rose-bushes, with- 

 out eyes, wings, or legs, 

 but with slender sucking 

 proboscis. The male is 

 winged and without 

 mouth-parts. (Photo-mi- 

 crograph by Geo. C). 

 Mitchell.) 



same manner. The palpi of both maxillae and labium 

 are wholly wanting in Hemiptera and the flexible needle- 

 like maxillae and mandibles are enclosed in the tubular 

 labium. This order is a large one and includes many 

 well-known injurious species, as the chinch-bug (Blissns 

 leucopterus), which occurs in immense numbers in the 

 grain-fields of the Mississippi valley, sucking the juices 

 from the leaves of corn and wheat, the grape Phylloxera 

 (Phylloxera vastatrix), so destructive to the vines of 

 Europe and California, the scale insects (Coccidce] (figs. 



