242 ENTOMOLOGICAL SOCIETY 



accident in his dissections, by means of which parts normally con 

 nected were torn apart and applied to others with which they 

 had no intimate relation. By this means it was made to appeal- 

 that the hemipterous mouth agreed with his previously conceived 

 idea of the mouth of the dipterous insect. Previous to Prof. 

 Smith's studies, the mouth structure of the Hemiptera,* w^hile 

 not elaborated in detail, was w r ell understood, and the major 

 features had been described by all the older writers on insect 

 morphology, all agreeing, practically, in the following characteri 

 zation, which I quote from Westwood : 



"The mouth is of the Promuscid construction, the labium or 

 canal being occasionally greatly elongated and extending beneath 

 the body, and is either 3 or 4- jointed. The four internal delicate 

 setae represent the mandibles and maxillae ; the maxillary and 

 labial palpi are obsolete. The labrum is distinct, triangular, 

 more or less elongated, closing upon the upper side of the labium 

 at the base, when the setae enter the labial canal. "t 



Prof. Smith's explanation of the mouth-parts is, in brief, as 

 follows : Accepting theclypeus and labrum as hitherto conceived, 

 the first following sclerite on either side represents the mandibles, 

 and the two pairs of setae with the lateral sclerites, posterior to 

 the mandibles, together with the sheath (the labium or main 

 part of the beak), represent altogether the maxillae. Of these the 

 setae, both of which are incorrectly made to attach to the sclerite 

 following the mandible, represent the lacinia and stipes, the 

 sclerite itself the palpus, and the sheath the subgalea and galea. 

 Prof. Smith's mentum, which is rather indistinctly described, 

 seems to be the hypopharynx. 



The studies which I have made of the mouth structure of the 

 Cicada have convinced me that the older authors were in the 

 main correct in the understanding and description of the homolo- 

 gies of the mouth of this order ; and the most interesting result is 

 the striking similarity, in spite of seeming divergences, in the mouth 

 structure of the true bugs with the biting orders, and, indeed, 

 with the typical insect mouth, which in all orders presents a 

 fixed and uniform plan of structure.]: 



* This term applies throughout to both the Hemiptera and to Homoptera. 



t Westwood, Classification of Insects, II, p. 452. 



I The terms " mandibulate" and " haustellate," used to -separate into 

 two groups the class Insecta, are misleading, since insects falling under the 

 latter appellation also possess lateral jaws representing mandibles and 

 maxillae. The misconception in these two terms was pointed out by 

 Westwood (I, p. 8), who emphasized the fact that the variation in mouth 

 structure was rather in the action of the various organs than in any impor 

 tant difference in type of structure. He says, "When the lateral pieces 



