Plant- Lice and Scale-Insects. 87 



of the sun after a cold wet day, and returning them again in fine weather 

 in the same manner as they care for their own larvae and pupae. I have 

 frequently observed them in April and May, when turning over stones in 

 search of facts and specimens, and noticed the eagerness and activity of an 

 unroofed household of ants in carrying down into their galleries the little 

 root-lice and their own larvas with equal solicitude. 



Mr. B. D. Walsh of Rock Island, 111., one of the most accurate and 

 thorough-going observers, has ascertained that the ants also bring home 

 to their nests the young Pemphigus from the roots on which they art- 

 feeding, even at some distance, and, in one instance, when the nest was 

 situated in a decayed stump over a foot from the ground. 



The Aphides^ as a group, differ widely in habits, and detail of structure ; 

 those living upon roots never ascending to leaves or twigs, and vice versa. 

 They are readily recognized by their seven-jointed antennae, two-jointed 

 tarsi, and honey-tubes. The majority of the larger wingless ones we see 

 are females ; and many a keen student is now ciphering at the problem of 

 an ovo-viviparous race of animals, living and producing for more than a 

 dozen generations without males. Fig. i represents a common species in- 

 festing the white birch ; Fig. i, «, the head from the front, with haustellum. 



Fig. 1. 



or sucker. The color of this species, and of the greater number that I am 

 acquainted with, is light green. The cerasi and some others, however, are 

 quite black or very dark colored. All the species are akin in their sensi^ 

 bility to strong soap-suds, tobacco-water, or the fumes of burning sulphur ; 

 either of which remedies, as occasion may determine, will be found per- 

 fectly efficacious if faithfully applied. 



