HEMIPTERA. 141 



same side. The aspect of the head and body and of 

 the fore pair of wings and the halteres is quite distinct 

 from those of the Diptera, and the more careful 

 observer readily recognizes that the insect belongs to 

 the Homoptera. Such resemblances in the form of 

 the body and its organs are not infrequent in the 

 animal kingdom between animals belonging to widely 

 different stocks, and are spoken of as representative, 

 parallel, or homoplastic forms. 



The only function of the male is reproduction ; he 

 does not, therefore, eat anything, and the useless 

 mouth parts are lost. This singular creature has also 

 another remarkable peculiarity, the lost mouth parts 

 are replaced by an additional pair of eyes. 



The mealy bugs, Dactylopius, so common on green- 

 house plants, do not lose the power of locomotion, and 

 in place of the scale the body is often covered with a 

 cottony excretion.^ The cochineal bug, Coccus cacti, 

 is a native of Mexico. The well-known dye is made 

 of the female insects which are killed and dried. 

 Lake and carmine are also prepared from cochineal. 



The lac-insect, Carto'ia lacca, is obtainable in 

 what is called stick-lac. This substance is composed 

 of the twig and incrustation made up of the gummy 

 resin of the plant, the scales of females, and the bodies 

 of their young. The females pierce the plant and the 

 resins that exude make the scale more effectual as. 

 a protection for the eggs, and also answer as food for 

 the larvae. Shellac, the well-known varnish, is made 

 from the incrustations of stick-lac. 



1 Comstock, Introd. to Entomology, p. 138, and Report for 

 1880. 



