TEOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING .551 



Pseudococcusvirgatus. The female when treated with KOH 10 ^er 

 ■cent, turns light brown and begins to clear up 3-4 minutes after boiling. 



Phenacoccus hirsutus. When treated with KOH 10 per cent, turns 

 bright pink and begins to clear up after 3-4 minutes. 



In prepared and mounted specimens the three species may be 

 separated first by their antennae and then by their pygidial ends. 

 The antennae in Pseudococcus corijmhatus are T-jointed, whilst in Phena- 

 coccus hirsutus they are 9-iointed. The anal lobes on the pygidial ends 

 are also important characters to differentiate with. 



On the cotton plant the three species of mealy-bugs occur together. 

 But for the last two years we have had much to do with P. corymbatus 

 and P. hirsutus. Both occur together on- the cotton top-shoots and 

 in some cases their ovisacs are so closed together that they form a whitish 

 patch 10 to 15 mm. long. When several hundreds of these are present 

 together on the stems and top-shoots these appear white from a distance 

 as seen in the photographs above. The effect is that the top-shoots 

 become hard and compact and the growth of the plants is retarded 

 considerably, with the result that the flowering jis well as the boiling 

 periods are delayed and a minimum number of bolls is put forth. These 

 too are not well developed and a good percentage of them falls o£E with- 

 the least shaking of plants and I think a majority of them become 

 affected with the internal Boll disease so much heard of in the West 

 Indies. No doubt a counting of these windfalls has shown us that a 

 good percentage of them is more or less affected by the boll worms. 



Pseudococcus corymbatus (Plate 94, fig. 2, and Plate 95). The eggs 

 lie touching each other within the female o^'isac. Each egg is from -32 

 to -36 mm. long and "15 to -18 mm. broad, cylindrical, rounded at^both 

 ends, somewhat broad in the middle, dark castaneous. The chorion 

 covered with a fine whitish meal. When fully matured, one end 

 becomes translucent under the microscope (aaxb Zeiss) and the 

 fully matured nymph can be seen within. When the nymph hatches 

 a slit opens towards the end' suffused with dark chocolate and the 

 nymph comes out, leaving the empty eggshell in the female ovisac. 

 These appear as pale white shrivelled pellicles interspersed freely 

 in the female ovisacs and appear distinctly under the microscope in 

 contrast with the chocolate brown eggs and the whitish threads of 

 the ovisac. 



After hatching the nymph moves about in search of food and as 

 soon as it comes upon a succulent place it fixes itself and begins to feed. 

 In the majority of cases observed the nymphs congregated together 

 on the leaf-stalks and the stems of shoots. They are gregarious in 

 habit and a number of them may be seen together on the leaf-stalks 



