Rural School Leaflet. 



1047 



identity was determined only by studying their development. The 

 bristie-iike mandibles and maxillae have at their apices fine teeth with 

 which they can puncture the plant, and are usually of about the same 

 length as the tube; but in scale insects, as the San Jos^ scale, the 

 tube is very short and the bristles are two or three times as long as 

 the body. 



Moths and butterflies. — The mouth-parts of a moth or butterfly when 

 not in use are almost completely concealed. They are rolled up into 

 a tight spiral like a watch-spring on the under side of the head, Fig. 

 18 A. They are not inconspicuous because of their small size, for in 

 the adults of many of the larger Sphinx moths they 

 are nearly six inches long, but are concealed by the ^'^j 

 flattened scales which cover the body. The upper ^ r.^ 

 lip or labrum is reduced to a mere rudiment, the 

 mandibles or biting jaws are wanting, the lower lip 

 or labium is represented by the labial palpi, Fig. 

 18 Ip, which are porrect or rigid and project up 

 over and in front of the face. The coiled tube con- 

 sists of the two maxillae, which have been greatly Yig. iB,— Moth. A, 

 elongated and closely appressed to each other. ]\f^Z%Z"Sil:i 



B, head ivilh max- 

 illae uncoiled and 

 the two maxillae 

 separated at apex. 



C, cross section of 

 maxillae to show 

 the furrow, f, form- 

 ed by their appres- 

 si'on 



Each maxilla is hollowed out or grooved on its mner 

 surface, Fig. 18 C, and by the close apposition of 

 these grooves a tube is formed through which liquid 

 food can be drawn. Moths and butterflies obtain 

 their food in great part from the nectar cups of 

 flowers In some moths the tips of the maxillae are 

 armed with strong spines, with which they can lac- 

 erate the tissues of ripe fruits and set free their juices. 



The insecticidal poisons applied for biting insects have no effect 

 therefore upon sucking insects, because the sucking insects puncture 

 the plant tissue and feed upon the juices of the plant beneath the 

 poisonous coating on the surface. Since the poison cannot be taken 

 up with their food, it is not carried into their aHmentary canal, and its 

 application produces no changes in their life. 



Insects with Biting Mouth-parts: 



Grasshopper-like Insects : 



Crickets, katydids, meadow grasshoppers, locusts or grasshoppers. 



Beetles: 

 June bug or May beetle, Colorado potato beetle, lady bug, click beetle, flat- 

 headed appletree Dorer, firefly, rosebug, striped cucumber beetle, cucum- 

 ber flea beetle, pea weevil, blister beetle, plum curculio. 



