128 NATURAL ARRANGEMENT OF INSECTS. 



this structure ; and unless it be supposed that the insect 

 uses these feet to press out the juices of plants, we 

 may fairly suspect that they are employed in seizing and 

 wounding smaller insects, There can be no doubt 

 that these vegetable suckers tend, in general, to the 

 healthiness of the plant they feed upon, although their 

 numbers frequently cause much injury. They are, in 

 fact, the phlebotomists of vegetables; attacking them 

 when in the full vigour of their growth, and feasting 

 upon that superabundance of sap with which they then 

 abound. The plant lice, or Aphides, are the most expert 

 suckers of any of their tribe. The little family of Mem- 

 bracina, which represent these insects in Tropical Ame- 

 rica, are found clustered on the rich luxuriant shoots of 

 the Guava and other fruit trees, busily employed in 

 tapping the stem and sucking the juice.* As to the 

 geographic distribution of the tribe, we have very few 

 in Europe, and these are mostly of a small size : the 

 rest are distributed in the hot latitudes of the Old, but 

 chiefly in those of the New World. The pre-eminent 

 types (Cicadida)) as is usual throughout nature, are 

 universal, and one has been discovered of late years in 

 the New Forest in Hampshire. Many family groups, 

 and nearly all the natural sub-genera, are restricted to 

 certain geographic limits. Several of these are interest- 

 ing, either from the singularity of their form, or their 

 habits, the chief of which will be subsequently noticed. 

 (1 20.) The affinities of the Cicades to the Cimicides on 

 one hand, and to the lepidopterous order on the other, 

 have already been intimated ; but so much of error, of 

 late years, has been introduced about f Borders" in the 

 reigning systems, that we shall here again return to the 

 subject, by quoting the opinion of others. The union 

 of this tribe to the typical Hemiptera is so obvious, 

 that it has been well observed, " the affinity cannot be 

 disputed, without a distortion of some of the most evi- 



* Mr. Westwood attributes the first announcement of this fact to an 

 author who mentions it ten years after it fell under our own observation 

 in Brazil ; and then flippantly says, I was ignorant of the circumstance. 



