248 ENTOMOLOGICAL SOCIETY 



led to such an erroneous conception as would make the two pairs 

 of setae and the maxillary sclerites, together with the labium, 

 which is not a paired organ but a simple one, all represent the 

 maxillae. The true homology is so simple and obvious that it is 

 not necessary to take up Prof. Smith's argument in detail. It is 

 gratifying to find, however, that the homology of mouth struc 

 ture worked out by such careful students as Burmeister, West- 

 wood, and many others of the old school of entomologists, whose 

 work in the main in this direction has not been improved upon, 

 should in this instance prove to be correct in essential features. 

 To Prof. Smith, however, belongs the credit of having called 

 attention to certain features of the hemipterous mouth which had 

 not been previously noted, namely, the mandibular sclerite and 

 the following maxillary sclerite, both of which he correctly de 

 scribed, so far as their exterior face is concerned. Previous to 

 Prof. Smith's studies the mandibles and maxillae were supposed 

 to be represented by the setae alone, and in fact in the lower 

 families the exterior sclerite of the jaws so prominent in the Cica 

 das are either obsolete or minute and very difficult of detection. 



There is a very general misapprehension, popularly at least, 

 of the manner in which the hemipterous insect draws up nourish 

 ment from animals or plants. It is ordinarily conceived that 

 the beak, meaning the labium with inclosed setae, is thrust more 

 or less deeply into the food substance and the juices sucked or 

 pumped up into the mouth. My own observations of the habits 

 in this particular of a number of species of predaceous hemiptera, 

 together with the structure of the labium itself, convinces me 

 that the beak proper, namely, the labium, is never thrust into the 

 food substance in the least, unless accidentally where the material 

 is so soft that the beak enters without effort on the part of the 

 insect ; but that, on the contrary, the beak is merely applied 

 closely to the exterior of the food and the setae are thrust in and 

 the resulting flow of juices drawn by suction, probably accom 

 plished by expansions and contractions of the fleshy interior of 

 the mouth-parts, into the canal formed by the labium and the 

 setae. That the labium is never inserted is borne out by obser 

 vation in the case of Hemiptera sucking juices from larvae, the 

 larvae invariably being suspended or seemingly attached at the 

 very extremity of the beak.* In the case of plant-feeding 

 Hemiptera the same is true even of the Aphides. In the 

 cicada, for instance, which passes its long subterranean existence 

 on the roots of plants, although the beak is very large and robust, 

 the roots themselves show no signs of puncture other than a slight 



*Mr. Pergande informs me that his own observations on predaceous 

 Hemiptera are in full accord with this statement. 



