INSECTA. 153 



front. The whole insect is of a greenish color, with irregular patches of 

 darker hue. 



It measures rather more than 6"' in length. 



Habitat. Small streams during the summer. 



In their larval condition, and even when adult, these animals feed upon 

 other aquatic insects. The wound occasionally received upon handling the 

 Notonecta is very painful, and rather large, from the obtuseness of their 

 rostrum. 



NEPA (Water-scorpion). Hemiptera. Anterior tarsi of one piece, the 

 four posterior tarsi of two. The antennae forficulate, short, and three- 

 jointed ; rostrum short, obtuse, and curved beneath. The two anterior feet 

 with short coxae, and the femora much larger than the other parts. Body 

 straight, elongate, and presents an elliptical contour. Abdomen terminated 

 by two slender bristles, which are employed in respiration. 



In form they are elongate oval, depressed. Their color is testaceous or 

 dark-ash. They vary in length from \" to 4" or 5". The larger species are 

 tropical. 



Habitat. Fresh water streams preferring still water. 



The insect is a very poor swimmer, preferring to walk along the bottom of 

 streams. It flies at night with great rapidity, and takes wing by climbing 

 to the upper end of any twig growing in the water. The rostrum, as in 

 Notonecta, is short and obtuse and the wound inflicted very painful but not 

 at all dangerous. 



APHIS. Antennae, properly speaking, longer than the thorax, composed of 

 seven articles. The tarsi are composed of two articles; the antennae are fili- 

 form, or in the form of setae, longer than head, and composed of six to 

 eleven articles. Bodies short, oval, and soft, and furnished at the hinder ex- 

 tremity with two little tubes, knobs, or pores, from which exude almost con- 

 stantly minute drops of a fluid sweet as honey ; heads small, beaks long and 

 tubular ; eyes globular ; upper wings nearly twice as large as the lower, 

 much longer than body, nearly triangular, and gradually widened toward the 

 extremity ; they are almost vertical when at rest, and cover the body like a 

 sharp-ridged roof. (Harris.) 



Measurement. 1'"-2"' long. 



Habitat. A variety of plants. A. rosce is found on the rose-bush ; A. 

 brassicce, the cabbage. The irritation excited by the act of the insect se- 

 curing its food causes excrescences to grow upon various parts of the infected 

 plant. These are technically known as ' galls.' Thus a ' gall case ' is ob- 

 tained from the Dactylium racemosum. The pistachia galls are derived from 

 pistachia tree of Southern Europe. The Chinese galls are the product of an 

 imperfectly known tree. 



Coccus. Hemiptera. Tarsi each with but a single point, with a single 

 hook at end. Male without rostrum, but possessed of two wings, which lie 

 horizontally upon the body ; abdomen terminated by two setae. The female 

 without wings, and provided with a rostrum. 



OF THE 



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