MANUAL OF GENERAL AGRICULTURE. 



93 



A, 



slightly uncoiled. B, 

 head with maxillae 

 uncoiled and the 

 two maxillae sepa- 

 rated at apex. C, 

 cross section of 

 maxillae to show the 

 furrow, f, formed 

 ~by their appres- 

 sion. 



on the under side of the head, Fig. 

 16 A. They are not inconspicuous be- 

 cause 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 flattened 

 scales which cover the body. The up- 

 per lip or labrum is reduced to a mere 

 rudiment, the mandibles or biting 

 jaws are wanting, the lower lip or la- FIG. 16. Moth. 

 bium is represented by the labial head with 

 palpi, Fig. 16 Ip, which are rigid and 

 project up over and in front of the 

 face. The coiled tube consists of the 

 two maxillae, which have been greatly 

 elongated and closely appressed to 

 each other. Each maxilla is hollowed 

 out or grooved on its inner surface, 

 Fig. 16 C, and by the close apposition 

 of these grooves a tube is formed 

 through which liquid food can be drawn. Moths and but- 

 terflies 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 lacer- 

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

 Make drawings of the head of a moth as shown in Fig. 

 16 A andB. 



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 alimentary 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. 



