HEMIPTKRA. 



235 



puncture the rind of plants and then proceed to suck out the 

 sap, often leaving behind a distinct scar where the proboscis 



FlQ. 119.— PROBOSCtS or A Hkbiipteeon. 



has entered (fig. 120, a). The majority live on vegetable juices, 

 but some suck the blood of both vertebrate and invertebrate 

 animals. Four wings are, 

 as a rule, present ; but 

 these may be reduced to 

 two, as in the male Scale 

 insects, or none, as in 

 some bugs, plant-lice, and 

 female scales. There are 

 two distinct types of wing 

 seen — -one in which the 

 basal half of the fore- 

 wing is leathery, the 

 other half transparent, 

 known as a hemielytron ; 

 in the seopnd it is quite 

 clear and membranous. 

 The former type is found 

 in the section of Hem- 

 iptera called Heteroptera 

 (fig. 126), the latter in 

 the Homoptera (fig. 121). 

 At one time these two 



sections were considered two distinct orders of insects. They 

 are now always united together under the order Hemiptera. 

 The Hemiptera all undergo an incomplete metamorphosis, 



Fig. 120. — Hop damaged by Hemiptera- 

 heteroptera. 



(a) By Calocoris fnlvomaculatus ; (&) liy Avtlio- 

 coris nemorum ; showing scars (o), and lioles {b). 



