12 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Plate I, figure 1, is an illustration of an apterous, viviparous 

 Schizoneiira lanigera, which will serve to represent the location 

 of one type of these glands. In this species they seem to be 

 distributed in a uniform manner over the entire body. In ap- 

 pearance they resemble the blastula stage of an egg. (Sec fig. 



1, B.) These glands are not composed of a uniform number of 

 cells, but range in number up to twent}^ ; and it is from these 

 that the flocculent or woolly material comes. 



Figure 2 is a gland of similar function which is found in Pem- 

 jihigns hurrowi. The material elaborated by this gland is more 

 of a pulverulent nature than that secreted by lanigera. It also 

 seems to be more impervious to water than the former. The 

 glands are not as numerous in number, but they contain more 

 cells than the other form. 



In the first-mentioned type we find the production to be of 

 a woolly or flocculent nature in appearance, but in composition 

 it is more like asbestos, since it may be pulverized into a fine 

 powder. In its normal state it acts as a protection against 

 water, as also doubtless against extremes of weather, for this 

 species is known to live in a temperature of 21 deg. F. Under 

 favorable conditions this covering grows at the rate of eight 

 millimeters or one-third of an inch per month, as was demon- 

 strated recently in this laboratory. 



Subfamilies of tlie Apliidicbv. 



, ( Winged form unknown ; subterranean in habit Rhizobiinaj. 



 '/ Winged form known ; areai in habit 2. 



( Antennae three- to five jointed ; fore wing with only two diecoidals. 



2. ] Chermaphinje. 

 ( Antennte six- to seven- jointed ; fore wing with three diecoidale 3. 



q S The third discoidal simple Pemphigicae» 



 ' / The third discoidal branched 4. 



. ( The discoidal with only one branch Schizoneurinae. 



 / The discoidal twice branched 5. 



c \ Antennae six-joint-^d Lachninae. 



 1 Antennae seven- jointed, rarely only six jointed Aphidinae. 



Subfamily RHIZOBIINAE Passerini. 

 Antennae five-jointed and short. Eyes small and inconspic- 

 uous, or none. Beak variable in length. Wings never acquired. 

 Legs short and well developed. Tarsal claws not always dis- 

 tinctly separate, and sometimes only one is present, as in Rhizo- 

 hius. Body somewhat short and somewhat convex dorsally. 



