302 The Ohio Journal of Science [Vol. XVI, No. 7, 



anterior edge of the frons is the broadly rectangular clypeus, 

 and at the distal edge of the latter is seen the small peglike 

 labrum. At the sides of the frons and clypeus, two small 

 semi-circular plates are seen, these are the lorse. The genae 

 are the large regions extending from beneath the eyes to the 

 anterior edge of the clypeus and completely surrounding 

 the lor£e. The rostrum or beak projects from under the surface 

 of the clypeus and encloses the setae. The head is greatly 

 deflexed with the result that the rostrum lies between the 

 anterior coxae and projects in a caudal direction. 



The same regions as are seen in the Jassoid head are to be 

 differentiated in the Cicada, or any other of the Auchenor- 

 rhynchous Homoptera. In 1896 Marlatt drew attention to 

 the fact that the frons of Cicada septendecim was really the 

 clypeus, that the clypeus and labrum constituted the labrum, 

 and that the lorae were the external representatives of the 

 mandibles, while the genae were the corresponding pieces of 

 the maxillae. No attempt was made to homologise the various 

 parts, until the work of Muir and Kershaw appeared in 1911. 

 From a study of the external and internal anatomy as well as the 

 development and embryology of both Homopterous and Het- 

 eropterous forms, these authors concluded that the "frons 

 of many writers was the clypeus, and their clypeus was the 

 labrum. The lorae have no connection with the mandibles, 

 but are lateral developments of the clypeal region. The dorsal 

 and outer pair of setae are the mandibles, developed direct from 

 the first pair of appendages behind the stomodaeum of the 

 embryo, and articulated in their normal position, viz., on the 

 oral margin between the clypeus and the maxillae. The ventral 

 and inner pair of the setae are part of the maxillae developed 

 directly from the distal joint of the second pair of appendages 

 behind the stomodaeum of the embryo, the basal joint being 

 directly developed into the maxillary plate." In a paper on 

 the Development of the Mouthparts in Homoptera, the same 

 authors conclude that "(1) The mandibles and maxilla arise 

 as in other insects, the former being articulated in an approxi- 

 mately normal position. (2) The Homopteran and Heterop- 

 teran mouthparts arise and develop in the same manner. 

 (3) There is no mandibular plate. (4) The tentorium agrees 

 essentially with that of other insects. (5) The maxillary 

 seta does not represent the palpus, but may be a development 



