148 BRANCH ARTHROPODA 



male has but a single pair of wings and has no organs for procuring food. 

 The mouth parts disappear during metamorphosis and a second pair of 

 eyes develops. The adult female is always wingless and the body is always 

 scale-like or gall-like in form, or grub-like and clothed with wax. Those 

 of some species retain their eyes, antennae, and legs, while others are fixed 

 in adult life and very degenerate, lacking eyes, antennae, wings, and legs. 

 In speaking of the San Jose scale, Kellogg says, " it has a long, fine, flexible 

 process projecting from near the center of its under side, this is its sucking 

 proboscis, and serves as a means of attachment as well as an organ of feed- 

 ing." The San Jose scale is very prolific. It was ascertained at Washington 

 that there are four regularly developed generations and possibly part of a 

 fifth in a year. It is estimated that about 200 females (and about the same 

 number of males) are given birth to by each female. Thus the descendants 

 of a female amount to 3,216,080,400 individuals. From this it can easily 

 be seen how destructive to fruit trees this pest soon becomes. It is now 

 found in every state and territory and in Canada. Many states have 

 laws to try to prevent its distribution with nursery stock. 



Perhaps the most effective remedy is the fumigation of orchard trees by 

 hydrocyanic gas. To do this the tree is entirely enclosed in a large tent 

 and the gas generated under it " by pouring about 50 ounces of water into 

 5 ounces of commercial sulphuric acid and dropping into it 15 ounces of 

 cyanid of potassium." These amounts are sufficient for a tree 12 feet high 

 with a spread of 10 feet. The fumes are deadly poison. Of sprays for 

 leaves and greenhouse plants, crude petroleum and kerosene emulsion are 

 best. Protection of the birds is one great means of holding these pests in 

 check. It has been proved by the examination of 226 stomachs that more 

 than one-fifth of the food of the blackheaded grosbeak (Zamelo'dia melano- 

 ceph'ala 1 ) consists of scale insects. For the work (Fig. 118) of ladybird 

 beetles see p. 147. 



ORDER vin. COLEOP'TERA 



This order consists of eleven or twelve thousand species in 

 America, north of Mexico. 



The mouth parts of beetles (Fig. 119) consist of the upper 

 lip or labrum, the jaws or mandibles for seizing the prey or for 

 gnawing; the complicated many pieced maxillce with usually 

 prominent maxillary palpi; the lower lip or labium of several 

 parts, and rather large labial palpi. These mouth parts are 

 adapted for biting, and are not easy for beginners to identify. 

 The student should identify these parts on a large beetle with 

 the help of a good figure (Fig. 119) and a good magnifying 

 glass. 



Compound eyes are present, but usually the simple eyes are 

 wanting. 



The wings are four in number, except in some ground beetles, 

 which have only the anterior pair. The anterior wings are 

 1 Plate III, Bulletin 32, U. S. Biological Survey. 



