8 MEDICAL ENTOMOLOGY 



C. Third subtype Stablefly, closely ensheathed heavy pierc- 

 ing structures, two in number. 



D. Fourth subtype Housefly, suctorial muscular proboscis, 

 but not suited to piercing. 



5. Hymenopteron type suctorial, lapping form, as in the 

 honeybee and ant, mandibles modified for portage and combat. 



6. Lepidopteron type suctorial, coiled tube form, as in the 

 cabbage butterfly. 



EXERCISE 1 



A STUDY OF INSECT MOUTHPARTS 



A. Orthopteron type. 



To illustrate this type either the grasshopper or the cockroach 

 may be used, but since the former is more easily obtainable and 

 can be handled more satisfactorily it will serve this purpose very 

 well. This type, the mandibulate or biting, is the generalized or 

 primitive form, and will serve as a basis for later comparisons 

 and derivations. 



If the head of the grasshopper is viewed from the side and 

 again from the front the relative position of the parts will be 

 better understood. 



Separating the structures composing the mouth of the grass- 

 hopper, the following pieces will be observed. In front, low 

 down on the head, hangs the labrum, or upper lip, attached to 

 the clypeus, easily lifted as one would raise a hinged lid, the 

 hinge line being at the lower part of the sclerite known as the 

 clypeus. 



The labrum functions as does the upper lip in higher animals, 

 in that it draws the food toward the mandibles. In this the 

 labrum is greatly aided by a rough toothed structure called the 

 epipharynx, which forms the inner lining of the labrum and the 

 clypeus. Because of the close association of these two structures 

 they are often referred to as a double organ, the labrum-epi- 



