280 Tlie Development of Ceroplastes roseatiis. 



A week subsequently the caudal plate was entirely 

 merged into No. 3, and the insect, which now measures 

 externally 3 mm, in length, presents seven well-defined 

 plates. The apical tufts of snowy white secretion, which 

 contrast so noticeably with the roseate hue of the waxy 

 plates, are very minute and in many instances have dis- 

 appeared entirely. 



During the ensuing fortnight the secretion of wax 

 proceeds rapidly, the sutures between the plates are 

 completely filled, and the end of the stout anal process is 

 visible as only a small black point. The insect has 

 attained a length of 6 mm., on an average, and appears 

 as in Fig. 4. At this stage the rosy colour is most pro- 

 nounced at the recently filled sutures, and its existence 

 would seem in part due to the translucence of the newly- 

 formed wax allowing partial transmission of the deep 

 maroon colour of the living insect beneath. 



A fortnight later, almost exactly ten weeks from the 

 date of fixation, the $ had arrived at maturity and the 

 test was fully formed, presenting the appearance described 

 by Messrs, Townsend and Cockerell, with one addition, 

 viz, — that in the smaller and more perfectly formed 

 specimens (Fig, 5) the apex of the test is mucronate and 

 curved cephalad. 



The rate of growth of individual insects varies con- 

 siderably, their relative position upon a branch appearing 

 to have a marked influence upon development ; those 

 nearer the main stem or trunk seemingly thrive better 

 than others farther removed. The largest fully-formed 

 test in my series measures long. 10 mm., trans. 8 mm., 

 alt, 6 mm,, and the smallest 3^0 X 3 X 2 mm,, both being 

 of the same generation. Very few arrive at maturity owing 

 to the attacks of various parasitic Hymenoptera, amongst 

 which, however, I have succeeded in rearing only one, 

 Zecaniobius cocJcerellii, Ashm. They are also preyed upon 

 by the larvae of a Coccinellid, Azpa lutcipes, Muls. 



There are four broods a year, but owing to the causes 

 mentioned above their colonies are kept within very 

 narrow limits, and considered economically they are 

 innocuous. 



Explanation of Plate VIIL 



[See explanation facing the Plate.] 



