METAZOA INSECTA. 431 



female cottony cushion-scale, Icerya purchasi Maskell (PI. 

 1070, fig. i, dorsal side; fig. 2, lower side, colored from 

 life), has club-shaped antennae each bearing four long 

 hairs. It would be interesting to know the cause of the 

 elaborate development of these organs. The eyes are 

 situated on the margin of the head (see fig. 2) and are 

 raised on short tubercles. There are rows of pores and 

 many hairs on the body. In the second stage (fig. 3) 

 and also the third (fig. 4) the antennae are shortened, and 

 the eyes are no longer on the margin but on the ventral 

 side of the head. The pores and hairs are scattered 

 irregularly over the body. The adult female (fig. 5, dor- 

 sal view) is provided with tufts of black hairs around the 

 edge and with an immense number of pores. The wax 

 filaments" that issue from the pores are curly. Besides 

 these wax threads the animal produces glassy-like fila- 

 ments and. from one large pore in the back globules of 

 honey dew are ejected. When ready to lay her eggs, the 

 female lies flat on the back, the edges of the body turned 

 slightly upward, and the waxy material of which the sac 

 is composed begins to issue from countless pores on the 

 under side of the body, but more especially along the 

 sides below. As the secretion advances, the body is 

 raised, the forward end being still attached, until, near 

 the completion of the sac, the insect is apparently stand- 

 ing on its head nearly at right angles to the surface of 

 attachment (fig. 6, dorsal view ; fig. 7, side view, showing 

 the pale greenish gray form, and with part of the white 

 egg covering torn away, showing the eggs stained with 

 carmine) . The egg-laying begins as soon as a thin layer 

 of the secretion has formed on the under side of the abdo- 

 men, and it continues during the formation of the sac 

 (Riley). The egg-sac is snowy white, in striking contrast 

 with the reddish colored insect. From the middle of the 

 under side of the sac the larvae make their escape soon 

 after hatching. 



The male is less specialized by reduction than the 



