THE HETEROPTERA. 549 



Two hair-like appendages are attached to the tail ; and in some species, such as that 

 which is selected for illustration, the creature is further decorated with a tuft of downy 

 and snowy white hairs. Before the male has changed into the pupal form, both he and 

 his future mate have affixed themselves to the tree by means of their beaks, and have 

 remained motionless for several months. 



The change undergone by the female is, perhaps, the most singular in the annals of 

 entomology. In her preliminary stages, she was a brisk, active, six-legged little creature, 

 with antennae at her head and two long setae at her tail. But when she approaches the 

 state which we must call " perfect," though in truth the creature seems to lose perfection 

 as it advances in development, she fastens herself tightly to a branch, loses all vestige of 

 limbs, head, or the least sign of her insect condition, the edges of her body enlarge, 

 and are pressed closely to the bark, and her back swells enormously, until she looks like 

 one of the galls that are often found on bark, and bears no small resemblance to a 

 limpet with rounded back. In some species, the body is enveloped in a white cottony 

 secretion, and in others a kind of wax is poured forth. The only advantage which she 

 seems to possess over the male is, that she has a three-jointed beak, which she can drive 

 into the tree, and by means of which she can obtain the nourishment necessary for 

 this enormous growth. The male, on the other hand, has t no mouth at all, nor does 

 he need one. 



Within the shell-like body the young Cocci are hatched, amid an abundant supply 

 of white substance, something like flour. The mother by this time has died, but her 

 shelly skin still remains, and forms a house wherein her children live until they are 

 strong enough to enter the world. They are usually hatched towards the end of June, 

 and the young escape at the end of July. 



The COCHINEAL INSECT (Coccus Cacti) belongs to the same genus. This species is a 

 native of Mexico, and lives upon a kind of cactus, called, from its insect guest, the Cactus 

 cochinelltfer. The wonderful amount of rich colouring matter which these insects contain 

 is well known. The beautiful colours carmine and lake are obtained from this insect, 

 and the best scarlets are likewise produced from the Cochineal, the difference of hue 

 being due to a mixture of chloride of tin. The trade in the Cochineal is very great ; and 

 as the substance is very costly, and permits a parcel of great value to be compressed into 

 a small bulk, it is often used in lieu of cash in mercantile transactions, and a package 

 will go travelling backwards and forwards for a long time before it reaches its final 

 destination. 



Several other species, such as the POLISH SCARLET GRAIN (Coccus Polonicus), and the 

 KERMES ( Coccus Ilicis], are also valuable to colourists, and impart a very fine scarlet to 

 substances treated with them, although the hues are not equal to those obtained from 

 the cochineal. The latter of these insects was known both to the Greeks and Romans, 

 and was used by them for the purpose of obtaining the purple dyes which were so much 

 worn by the higher classes. 



The LAC INSECT (Coccus laced) is another member of this most useful genus. This 

 species resides in India and the hotter parts of Asia. It is found attached to the twigs 

 of trees, and is then called stick-lac, the shell-lac being the waxen secretion purified 

 and shaped into thin shell-like plates. 



HETEROPTERA. 



THE insects belonging to the large and important order which is placed next to the 

 Homoloptera, are readily known by several conspicuous characteristics. The wings 

 are four in number, and the front pair are very peculiar in their structure, the basal 

 portion being horny, like the elytra of beetles, and the remaining 



ig portion membranous 



