ANTENNiE. ROSTRUM. xlvii 



antennae of insects. If these important organs are 

 the only auditory organs in the Strichilantes, or singing 

 Cicadaj, they are curiously disproportionate to the large 

 and loud-sounding apparatus of the males. Stridula- 

 tion, humming, and buzzing are so common in insects 

 that it is remarkable that the corresponding recipient 

 organs for aerial vibrations have hardly yet been proved 

 to exist, — unless the antennal hairs and the antennal 

 tympana may be regarded as such. 



Sir John Lubbock leans to the opinion that the 

 antennae are olfactory organs ; yet, taking other things 

 into consideration, he thinks that the sense of smell 

 in insects need not be confined to these organs alone. 



The Rostrum. Schnahelscheide, 



This sucking organ rises from the hinder part of the 

 clypeus, and is carried horizontally between the cox^e. 

 It varies in length, but it is never very long. It is 

 composed of three joints, the first two of which are 

 cylindrical and unequal. The basal joint is often con- 

 cealed under the labrum. Four sharp horny pieces 

 are present, one of which — forming a sheath to the 

 others- — runs down the length of the rostrum, to con- 

 stitute the sucking tube, as seen in other Homoptera. 

 None of the Cicadae apparently possess glands for 

 secreting irritant poisons, as may be noted amongst 

 the Aphides, which positively kill some plants by their 

 irritative punctures on the leaves. 



The four labial pieces of the mouth, converted into 

 lancets in the Hemiptera, are styled ''promuscis" by 

 Kirby and Spence, and these authors regard this com- 

 bination as distinct from the proboscis of Fabricius, 

 which is considered by them to be a sucking tube with 

 no lancets. 



I here use the general term rostrum, and, as in the 

 Aphides, I count normally three contained lancets, 

 although only two appear on Plate A, fig. 7. 



