HEMIPTERA. 



261 



(fig. 150, a). The majority live on vegetable juices, but some 

 suck the blood of both vertebrate and invertebrate animals and 

 man, and even carry disease. Four wings are present as a rule ; 

 but these may be reduced to two, as in the male Scale insects, 

 or none, as in some bugs, plant-lice, and female Scale insects. 

 There are two distinct types of wing — one in which the basal 

 half of the fore-wing is 

 leathery, the other half 

 transparent, known as a 

 hemielytron ; in the second 

 it is all clear and mem- 

 branous. The former type 

 is found in the section of 

 Hemiptera called Heterop- 

 tera (fig. 159), the latter 

 in the Homoptera (fig. 

 151). At one time these 

 two sections were con- 

 sidered two distinct orders 

 of insects. They are now 

 united together under the 

 order Hemiptera. 



The Hemiptera undergo 

 an incomplete metamor- 

 phosis, there being little 

 difference between the 

 larva, pupa, and imago in 



many genera. The pupse are always active except in the Scale 

 insects and Snow-flies. The larva, which also resembles to a 

 certain extent the adult, moults its skin several times, and 

 then, if it is destined to become a winged form, it develops 

 rudiments of wings as small bud-like lateral outgrowths on 

 each side of the thorax, the pupal stage, which after a time 

 casts its skin and becomes the adult {vide fig. 159). The 

 ova of the Hemiptera are often beautifully sculptured bodies. 



FlQ. 150. 



-Hop damaged by Hemiptera- 

 heteroptera. 



- (a) By CaZocoris fidvomaculatus ; (p) by Antho- 

 coris nemorum ; showing sears (ft), and holes (^). 



