Vtr. CuRTis's OhfcrvaticKS on Aphideu ;3 



which infefts plants very generally^:', while the {Avae /pedes, on a 

 geranium that I kept within doors, jirodiiccd young. In mild 

 winters I have obfcrvcd, in the month of January, the fame fpecies 

 of Aphis in great numbers on various fpecies of primula without 

 doors, and all the females viviparous. Thefe are fafts which prova 

 that all Aphides are not oviparous and viviparous at the fame feafon 

 but that fome may be wholly viviparous ; that all fuch as are. 

 both oviparous and viviparous do not lay eizgs tc.ward the middle o£ 

 autumn, nor at all during the winter, unlcfs a certain. de"-rce of cold 

 takes place. 



Moft people will think it a matter of very httle moment to man^ 

 kind whether an Aphis comes into the world with its head or its- 

 heels foremoft :— it maybefo; yet, ag nature's hiftorian, it is per- 

 haps incumbent on us to notice this cuxumflance. The young Aphis. 

 then is ufhered into the world with its feet foremoft, fee Tab. V. 

 fig. I., and this a6l of partiirition, unimportant as it may appear, 

 ferves to difplay the wifdom of the all-provident Author of Nature. 

 The female Aphis, i&ufually delivered of its offspring as it fits clofe 

 to the bark of the tree, but not fuddenly and all at once. Two- 

 thirds of the body of the young one is quickly protruded. When it 

 gets fo far, the power of expulfion ceafes, and the delivery proceeds- 

 flowly. Time is thus given to the young one to learn the ufe of its 

 legs, which it foon kicks about brifldy, and the firft fervice it em- 

 ploys them in is to clean away a white fubftance, the remains 

 perhaps, of the membrane in which it was enveloped in, the womb.. 



• Thefe eggs were laid in fmall, irregular groups, on the upper as well as on the 

 under fide of the leaves; they were of a perfeftly biack colour, and very viGble to the. 

 naked eye. I found afterwards that the eggs when recently excluded were green, from' 

 which colour they griduaUy changed to that which rendered them fo confpicuous. 'xhey 

 were nightly attached to. the leaf. 



But 



