PE0CEEDI3SGS OF THE THIRD ENTOMOLOGICAL MEETING 373 



As, however, the contents of the body show through the skin the abdomi- 

 nal region looks brownish. The grubs pupate uiside the stems. 



The full seasonal life-history is not known. From grubs collected 

 in March and April weevils appeared by the end of May. 



The Weevil Borer (C. S. 1397). (Plate 33, fig.2.) 

 Foodplant — Motlia {Cyperus rotundus). 

 Legless pale-yellowish-white grubs, boring the stem and causing dead 

 heart were collected on 22nd May and weevils emerged from these in the 

 Insectary between 13th and 17th June. 



The purple-coloured Zeuzerid Borer (C. S. 1805). (Plate 34.) 



Foodplant — Kanra (Saccharum arundinaceum). In the Insectary the 

 caterpillars, fed on maize and also on juar (Andropogon Sorghum) 

 to a small extent. 



This borer has only one generation in the year. Young caterpillars 

 have been collected from outside on the 8th July and gradually develop- 

 ing ones onward till about November when they become fullgrown. 

 Fullgrown hibernating and aestivating caterpillars have been collected 

 in winter and up to about May. Moths emerged in the Insectary be- 

 tween 15th June and 10th July. 



As usual with all internal borers, they cause " dead heart " in plants 

 and bore in the centre of the stem, converting it into a hollow tube. 

 The caterpillars go down right into the roots to hibernate and 



A fullgrown caterpillar measures about 35 mm. in length and aboi^t 

 4-5 mm. across the abdomen. The shape is cylindrical and slightly 

 tapering posteriorly. The head is red-brown and smaller than the 

 prothorax which is the broadest segment, measuring a httle more than 

 5 mm. across. The prothoracic shield is large, yeUow-brown in colour, 

 having on its hinder part a number of posteriorly-directed flattened 

 brown spines. The spiracles are elongated brownish shts and the five 

 pairs of prolegs are rather short but equally developed. The colour of 

 the body excepting that of prothorax is deep pmple. 



Pupation takes place inside the tuimel formed by the larva. Before 

 the emergence of the moth the pupa wriggles out to some extent through 

 an opening on the side of the stem previously made by the larva, the 

 mouth of the opening being left closed by a thin epidermal layer of the 

 bark. 



