CHAPTER XXV 

 THE HEMIPTERA 



The Hemiptera is a large group containing many insects which are 

 always injuriously active, and many more which occasionally become so. 

 They vary greatly in size, some being minute while others may attain 

 a length of four or five inches. They are most numerous in species in 

 tho warmer portions of the globe, but an abundance of individuals in 

 colder regions results in making them extremely common everywhere. 



Most Hemiptera have the dorsal surface of the body rather flattened, 

 though there are many exceptions to this statement, and the wings when 

 not in use rest upon this surface. The wings are nearly always present, 

 four in number, and the basal half, or sometimes more, of the front 

 pair is thickened and horny, resembling the elytra of beetles. The outer 

 end, however, is membranous and veins traverse this portion, so that the 

 fore wings are appropriately called hemielytra. The membranous part 

 of one wing largely overlaps that of the other when they are at rest. In a 

 few families the difference in the texture of the two portions is not very 

 perceptible but in most cases it is plainly evident. The hinder wings are 

 entirely membranous and when not in use are concealed beneath the 

 others. 



The body of the Hemipteron with few exceptions, shows no constric- 

 tion at the junction of thorax and abdomen and is usually widest at the 

 hinder end of the prothorax. The attachments of the wings behind 

 this do not occupy anywhere near all of the width of the body, and 

 directly behind the pronotum, between the wings, the space is taken 

 up by a rather large, usually quite triangular plate called the scutellum. 

 In some families this becomes greatly enlarged, covering more or less 

 of the dorsal surface of the body from the pronotum back, and in such 

 cases the wings in closing slip under this so that little besides their costas 

 show. 



Hemiptera are sucking insects (Fig. 159), obtaining their food by 

 piercing the surfaces of plants or animals and drawing into their own 

 bodies the sap or blood. The mouth parts in the group have been identi- 

 fied with those of chewing insects, but they have been greatly modified to 

 form a beak or rostrum which is attached to the front of the underside 

 of the head. The details of structure of the rostrum differ in different 

 Hemiptera but agree in general plan (Fig. 160). The outside of the 



168 



