Class 3. Insecta. Order 2. Bhynchota or Hemiptera. 259 



and thus, imlike all other members of the gi'oup, are holometabolous. 

 In several of the species it has been proved that the females can reproduce 

 parthenogenetioally. Several forms differ in certain respects from this descrip- 

 tion of the Ooccidse ; in some the females are locomotor throughout life and do 

 not remain attached over the eggs ; there are others, again, in which both sexes 

 possess four wings, and which thus offer a transition to the Aphides. As 

 examples may be mentioned : Aspidiotus nerii, the shield-hke female of which 

 is frequently met with on the oleander ; similar forms are very abundant on 

 uncultivated trees. Coccus cacti, the Cochineal-insect, lives on certain 

 Mexican species of cactus ; the males are dipterous and have long ceroi. The 

 females are wingless and bulky ; they do not cover the eggs with their bodies, 

 but smTOund them with wax threads as do many of the Aphides ; the cochineal of 

 commerce consists of their dried bodies. To this family belongs also the 

 Shellac-insect (Coccms Zacca), which is found in the East Indies on certain 

 species of figs, causing the flow of a resinoiis substance, shellac, from the tree : 

 and the Kermese-insect (Lecanium ilicis), which lives on a species of oak- 

 tree in South Em-ope ; from the spherical females a dye is obtained. 



Sub-Order 2. Heteroptera (Su^s). 



The fore and hind wings are dissimilar, the latter thin, naembranous 

 and adapted to flight; the former modified as elytra, which are 

 not thickened and leathery for their whole length, but only for 

 their basal halves or rather more, and the thin tips, when at 

 rest, overlap j the distinction into the two regions may, how- 

 ever, be quite effaced. The elytra cover the greater portion of 

 the mesothorax, the metathorax, and the abdomen, but a triangular 

 median portion of the mesothorax {scutellum) remains uncovered. 

 The proboscis arises anteriorly from the head, which is generally 

 small ; the prothorax is large and freely movable, the whole body is 

 usually flattened. In the land forms a pair of stink glands opens on 

 the ventral surface of the metathorax, and the secretion has an 

 extremely offensive odour. The Heteroptera feed on the fluids of 

 plants or animals (Insecta, Yertebrata). 



1. Land-bug (Oeocores) is the common term for a large number of 

 bugs (forming several families), charactei-ised by the possession of well- 

 developed antenna and a long proboscis. Most of them are terrestrial ; some 

 feed on plants, others are predaceous, sucking other Insects; some live as 

 parasites on Vertebrata. Many are gorgeously colom-ed. Abundant in temperate 

 zones, and especially so in the tropics. The Bed-bug {Cimex [Acanthia] 

 lectularius) is a flattened, brownish, apterous (rudiments of the fore wings 

 only ai'e present) form, which lives as a temporary parasite upon Man. It 

 came originally from the East Indies. Here also belongs the Hydrometra, a 

 slim, elongate form, which runs about actively upon its middle and hind legs 

 on the sui-face of freshwater ; the legs of the fii'st pair are considerably 

 shorter than the others, but ai-e fairly strong, and are used for catching Insects 

 upon which it feeds ; the abdomen is rather small, hardly longer than the 

 thorax. Closely allied to the Hydrometridse ai-e the Halobatidae, which run about 

 on the open sea : they are distinguished by the extraordinarily small size of the 

 abdomen. 



s 2 



