Mr. CuRTis's OhJavaUoHS on Aph'uks. f^ 



ytilative to their hiftory, and to make them more generally known, 

 will not, wc truft, be unacceptable to the public. Siicli inquiries 

 may pofllbly lead to the means of obviating; the injuries they occa- 

 fion ; and if they fail in this, they may tend at leafl: to corred the 

 erroneous notions entertained of blights, not by the vulgar and illi- 

 terate merely, but even by perfons of education, who may frequently 

 be heard to maintain that thelb infers are brought by the eafl winds ; 

 that they attack none but fickly plants ; with other notions, all as 

 falfe in facl as unphilofophical in principle. 



Locufts and caterpillars, famed for their devaflations, are far- 

 nilhed with flrong jaws, by means of which they crop and wholly 

 devour the foliage of plants. The Aphis dcflroys them in a different 

 way. Inftead of jaws and teeth it is provided with a hollow-pointed 

 probofcis or trunk* which, when the animal is uot feeding, folds 

 under its breafl:. With this inftrument it pierces the plant, and 

 imbibes its juices to fupport itfelf ; but thefe juices being efTential to 

 the life of the plant, it follows that, when they arc drawn off, 

 the plant, exhaufted, flags and perifhes, being in fact literally bled 

 to death by thefe leech-like animalcules. Yet, fo tenacious of life 

 are plants in a healthy ftate, that tliey in general only fall victims 

 to the continued attacks of thefe infeds when in immenfe numbers. 

 But it moil commonly happens that if they do not wholly deftroy 

 a plant they deface it, and a fmall number of Aphides are fufficient 

 to produce this effect. The leaves of fuch trees and plants as have 

 a firm texture ancJ flrong fibres, though infefled with thefe infe<5ls, 

 preferve their form; but the more tender foliage of others, and 

 flowers in general, cannot bear their punctures without curling up' 

 and becoming diftorted ; in confequence of which they lofe their 

 beauty entirely and irretrievably. The cultivators of plants, efpeci- 

 ally in ftoves and green-houfcs, cannot be too much on their guard 

 againft the whole tribe df Aphides yior with what pleafurc can a 



large. 



