112 INSECT TRANSFORMATIONS. 



not ascertained) was discovered by Reanmur to be 

 ovo-viviparons ; but the embryo flies were not ar- 

 ranged in the pouch in the same spiral form as the 

 preceding, but longitudinally. These did not appear 

 to be quite so numerous ; and they had a peculiar 

 breathing apparatus, which, when shut, as it could 

 be at pleasure, appeared in the form of a crown. 



Amongst several other ovo-viviparous flies dis- 

 covered by Reaumur, there was a very minute tipu- 

 lidan-gnat (species not ascertained) with a jet-black 

 body, white wings, and beaded antennae, not larger 

 than the head of an ordinary pin, which was bred in 

 great numbers from some cows' dung put into one 

 of his nurse-boxes for another purpose. He justly 

 remarks upon this circumstance, that " the minute 

 and the grand are nothing, or rather are the same, 

 to the Author of Nature." 



The numerous genus Ajjhis presents the singular 

 anomaly of producing eggs in the autumn and liv- 

 ing young during sumn.er, and, as Curtis tells us, 

 even during winter in green-houses. De Geer, how- 

 ever, ascertained that it was not the same individual 

 aphides which at one season produced young, and at 

 another eggs, but different generations *. By a series 

 of very careful and troublesome experiments, Bonnet 

 also ascertained the curious fact, that in three montiis 

 nine generations of these insects may be produced in 

 succession, though the males be rigorously excluded 

 from the nurse-boxes where the females are isolated. 

 In fact, all the aphides produced in spring from the 

 eggs laid in autumn, appear to be females; and no , 

 males are produced till the end of summer, a short 

 time before the eggs are deposited for winter. Among 

 both males and females are some with and some 

 without wings, — the nature of which distinction does 

 not appear to be yet ascertained. 



* De Geer, Mem. des Tnsectes, iii. 70. 



