1728 Insects. 



The Peruvians use it chiefly in the cultivation of maize and potatoes. A few weeks 

 after the seeds begin to shoot, a little hollow is dug round each root, and is filled up 

 with guano, which is afterwards covered with a layer of earth. After the lapse of 

 twelve or fifteen hours the whole field is laid under water, and is left in that state for 

 some hours. Of the guano bianco a less quantity suffices, and the field must be more 

 speedily and abundantly watered, otherwise the roots would be destroyed. The effect 

 of this manure is incredibly rapid. In a few days the growth of a plant is doubled. 

 If the manure be repeated a second time, but in smaller quantity, a rich harvest is cer- 

 tain. At least, the produce will be threefold that which would have been obtained 

 from the unmanured soil. 



" The haciendas of the valley of Chancay have, during the last fifty years, con- 

 sumed annually from 33,000 to 36,000 bushels of guano brought from the islands of 

 Chancha and Pisco. The price of the bushel of coloured guano is one dollar and a 

 quarter, and the price of the white from two to three dollars. The price has recently 

 undergone many fluctuations, in consequence of the great exports to Europe. 



" The employment of this kind of manure is very ancient in Peru ; and there is 

 authentic evidence of its having been used in the time of the Incas. The white gu- 

 ano was then chiefly found on the islands opposite to Chincha ; so that for upwards 

 of six hundred years the deposit has been progressively removed from those islands 

 without any apparent decrease of the accumulation. The uniformity of climate on a 

 coast where there is not much rain must contribute to render the Peruvian guano a 

 more arid manure than the African, as fewer of the saline particles of the former being 

 in solution, they are consequently less subject to evaporation." — TschudVs Travels in 

 Peru. 



Remarks on the Introduction of Exotic Insects into Collections professedly British — 

 I had no desire to reply to the remarks of my friend Mr. Stephens, published in 

 the February number (Zool. 1615) respecting certain species of Lepidoptera in- 

 troduced into Catalogues of British Insects, the indigenous origin of which is ques- 

 tioned by many entomologists ; but having received letters from several friends ex- 

 pressing a wish that 1 should do so, I will pen a few remarks upon the subject. I be- 

 lieve, with Mr. Stephens, that there is a " growing disposition " to strike out of our lists 

 the number of foreign and imaginary species with which they have so long been encum- 

 bered, and I am willing to bear all the blame of having been one of the first to endea- 

 vour to arrive at the truth ; and having no published opinions to defend, I think I can 

 take an unprejudiced view of the subject. I cannot believe that any entomologists 

 have wished to strike out species from our indigenous list, solely from the hope of more 

 speedily completing a collection, by diminishing the number of desiderata ; I am more 

 inclined to suppose that there is an increased desire to examine for themselves, and not 

 blindly to follow their predecessors without once inquiring whether they were right or 

 wrong. 



Fully aware of the irregular appearance of many insects, I must still doubt the 

 British origin of some species contained in the older cabinets. I will take Mr. Plas- 

 tead's as an example. This eollcction contained Colias Philodice, a well-known 

 North American insect, which has never been captured in Britain or any part of Eu- 

 rope; Hipparchia Hero and Arcanius, said to have been taken in Ashdown Forest ; 



