SUBFAMILY MONOPHLEBINAE 67 



females. The wax is excreted from the cerores of the ventral 

 aspect and surrounds the eggs. The threads of wax from the 

 different cerores melt together as they come into contact. - The 

 characteristic external part of the ovisac is formed by the mar- 

 ginal band of cerores. The fluted external surface is produced by 

 the scalloped arrangement of the bands of cerores. The homo- 

 genous appearance of the wax is due to the melting together of the 

 wax from adjacent cerores. The fine granular wax of the dorsal 

 aspect is excreted by the cerores of this region. The long glassy 

 threads of wax are poured from the very large cerores of the dorsal 

 aspect. The cerores excreting these glassy threads are more 

 abundant upon the head and thorax. The difference in the 

 appearance of the wax of the dorsal aspect and that of the ovisac 

 is probably due to the fact that in the former the cerores are 

 distant from each other and there is no opportunity for the threads 

 from adjacent cerores to melt together. 



The large fluted ovisac of purchasi, while characteristic of 

 this species, is not found even in all the species of the genus 

 Icerya. The females of the great majority of the species of this 

 subfamily do not form ovisacs of the purchasi type, although all 

 of them form a greater or less abundance of white wax. This wax 

 is usually described as cottony and as forming indefinite masses 

 which are used as much by the female in covering her body as in 

 covering her eggs. A striking exception to this is found in the 

 genus Stigmacoccus, where the body of the adult female is enclosed 

 in a thin more or less spherical hard waxy test with an apical 

 aperture through which half of the body of the female may be 

 extruded. A few species live in ant 's nests and the amount of wax 

 excreted is always small. 



The female, as soon as a thin sheet of wax marking the 

 beginning of the ovisac is formed, begins to deposit her eggs. The 

 number of eggs in purchasi varies according to the condition of 

 the plant upon which the female has been feeding. Gossard 

 counted 600 to 800 while Koebele counted over 1,000 in a single 

 ovisac. 



The life history of the male has not been so accurately 

 described as that of the female. In the first nymphal stage, the 

 males are indistinguishable from the females, but in the second 

 nymphal stage differ in having a longer more slender body and 

 longer and stouter antennae and legs. The antennae consist of 

 six segments and are similar in form to those of the female. 



