Chionaspis. \ 09 



IV. Lobes present in early adult : afterwards obliterated by deposition of 

 chitin. Female insect enclosed within the tissues of the plant. Four free 

 abdominal segments. No circumgenital glands 'i\. fodie^u. 



V. Lobes altogether absent. Four free abdominal segments above the 



pygidium. 



A. Circumgenital glands in five groups. Female scale concealed within 



gall-like swellings on the plant. Prominent marginal processes on 

 pygidium simulating lobes 25. galliformens. 



B. Circumgenital glands in seven groups. Female scale concealed beneath 



the leaf sheaths of the plant. No marginal projections on pygidium. 



26. simplex. 



EXPLANATION OF PLATE XXXI. 

 Pygidial Characters of Chionaspis. 

 Fig. I. Extremity of Pygidium of C//. w«J-J^«(^^y with approximate median 

 lobes. 



2. Extremity of Pygidium of Ch. polygoni; with separate median lobes. 



3. J, „ CV^ T'rtrzVt'.yrty with median lobes in cleft. 



4. Diagrammatic plan of dorsal surface of pygidium of typical 



Chionaspis. (A), Mesal space. (B, C, D, E, F), first, second, 

 third, fourth, and basal spaces, respectively. 



5. Plan of ventral surface of pygidium. (Lettering as mjig. 4-) 



