2O6 AN INTRODUCTION TO ENTOMOLOGY. 



are usually of medium or small size ; there is a great variation in the 

 form of the body, which makes it difficult to characterize the family. 

 The most available character for distinguishing these insects is the 

 structure of the wing-covers. These are almost always complete, and 

 composed of clavus, corium, cuneus, and membrane. At the base 

 of the membrane there are one or two cells ; otherwise the mem- 

 brane is without veins. See Fig. 175. Other characters of the fam- 

 ily are as follows : The ocelli are wanting ; the rostrum 

 and antennae are each four-jointed ; the coxae are sub- 

 elongate ; and the tarsi are three-jointed. 



It is impracticable to discuss here the divisions of 

 -cover this family ; I can only refer to a few of the more 

 oiP^ocap. common sp ecies. 



The Four r lined Leaf-bug, Poecilocdpsus linedtus. 

 This is a bright yellow bug, marked with black. It measures about 

 8 mm. (0.31 in.) in length. There are four longitudinal black lines 

 which extend over the prothorax and the greater part of the 

 wing-covers (Fig. 176). There is in many specimens 

 a black dot on the cuneus of each wing-cover ; and 

 the membrane is also black. This insect infests 

 various plants, but abounds most on the leaves of 

 currant-bushes and of sage. It punctures the 

 young and tender leaves, causing small brown FlG 

 spots ; but these are sometimes so numerous and Tu 

 closely placed that the leaves become completely 

 withered. This insect is sometimes very abundant during the spring 

 and early summer : and occasionally does great injury. No efficient 

 means of destroying it has been devised except to collect it by 

 jarring the bushes early in the morning while it is torpid. 



The Tarnished Plant-bug, Lygus pratensis. The Tarnished Plant- 

 bug is a very common member of the Capsidae. It is smaller than 

 the preceding species, measuring 5 mm. (0.2 in.) in length, and 2j mm. 

 (o.i in.) in its greatest width. It is exceedingly variable in color and 

 markings. It ranges from a dull bark brown to a greenish or dirty 

 yellowish brown. In the more typical forms the prothorax has a 

 yellowish margin and several longitudinal yellowish lines ; there is 

 a V-shaped yellowish mark on the scutellum ; the distal end of the 

 corium is dark ; and the cuneus is pale, with a black point at the apex. 

 This species has been reported as injuriously infesting the young 

 leaves of the expanding buds of pear, and also the unopened buds. 

 Sometimes a whole branch will be thus affected, and will die as the 



