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Apple and Pear Sucker 



strong spines which may direct or support the thread of secretion 

 alluded to above. 



(6) Internal structure (Figs. 13, 14). Inside this heart-shaped organ 

 are situated two kinds of glands both of which are of a waxy nature. 

 The larger of the two finds its exit through the aperture mentioned 

 above. This is demonstrated by the longitudinal section (Fig. 13). 

 It is a big coiled structure occupying the whole of the abdomen of a 

 larva and secreting the big thread of wax mentioned above. The 

 other consists of small glandular cells opening out through those pores 

 referred to already. They secrete fine, shining, small spine-like threads 



aperture to the 

 I outside 



pores 



Fig. 12. 



projecting from the extremity of the abdomen. This structure will 

 be clearly understood from a transverse section (Fig. 14). This organ 

 with the glandular structures is left behind when the nymph moults to 

 the adult insect. There is not a trace of these structures in the adult, 

 which does not secrete honey-dew. 



(iv) Wing Lobes. These begin to appear in the third instar. In 

 the second instar their places on the meso- and meta-thorax are already 

 marked, but in the third there are small protuberances in these places. 

 They become well developed in the fourth instar, while in the nymphal 

 stage they are broad and elongate, lying at the sides. There are also small 



