MARCH. 55 



found on the under part of the leaf, preferring this, not 

 only on account of its being more tender, but as affording 

 protection from the inclemencies of the weather. Occasion- 

 ally the root is the object of their choice, that of the Lettuce 

 being often observed so thickly beset with one species that 

 the whole crop has been rendered of little value. These 

 insects are sometimes winged, at others destitute of these 

 appendages ; in the spring they are viviparous (that is, pro- 

 duce their young alive), and in the autumn oviparous, de- 

 positing eggs, like other insects, in places where they are 

 hatched the following spring. There are six or seven genera- 

 tions during the summer, which accounts for their wonderful 

 increase ; and in the autumn three more are produced. If 

 the Aphides had not many enemies, their increase would be 

 so great as materially to lessen vegetation. The larvse and 

 perfect insect resemble each other so much as to be distin- 

 guished with difficulty, except by size ; the females are ge- 

 nerally apterous (that is, without wings) ; the antennae are 

 filiform, and seven-jointed ; the tarsi two-jointed, the first 

 very short. This family forms part of the order Homoptera, 

 The interesting and well-known family, Formicida, or 

 Ants, merits notice more extended than would be afforded 

 by the mere naming of the species. The members of it 



