402 PROCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 



The strength of the individual fibres is much reduced and they lose much 

 of their glossiness. , ■ 



BoUivorm Parasites. 

 Of the five parasites (two Braconids, two Ichneumonids and one 

 Chalcidid) Microbracon lefroyi is the most active, next to it the yellow 

 Braconid and then the others. That there is great variabihty of colour 

 in Microbracon lefroyi has been stated in a separate paper* by Mr. C. T. 

 Bnies, to whom all the Microbracon material was sent for examination. 

 The adults are very active in the fields during the day and may be seen 

 flitting briskly about the plants or resting in places advantageous for 

 oxnposition. The female Microbracon lefroyi is more robust than the 

 male and has a prominent ovipositor. In several instances Microbracon 

 lefroyi females have been seen entering the affected shoots and exserting 

 their ovipositor to reach their victims. The eggs are laid either on the 

 anterior or the posterior part of the Bollworm larva but in a large number 

 of cases examined during the past seven years a greatest proportion of 

 parasitized worms was found with the eggs of the parasite on their post- 

 erior ends. This was only to be expected since the larva normally 

 remains with its anal externity near the hole used for extrusion of frass. 

 The parasitized larva becomes restive and changes colour. If touched, 

 it squirms from side to side and is not able to move about, as in the 

 majority of cases the posterior end becomes rigid and shrunk. The 

 eggs are laid either singly or in groups of three or four or six or even 

 more. The largest number of eggs found laid on a parasitized worm 

 was 13, although in the Punjab as many as 21 have been found on a single 

 parasitized Bollworm. The eggs are shiny to dirty white in colour, 

 elongate, cylindrical, somewhat curved in the middle ; in some one end 

 is bioader than the other. The grub on hatching remains on the body 

 of the host and feeds by imbibition. The chitin of the grub is so thin 

 and transparent that the inner pulsations are quite visible under a high- 

 power objective. The grub is of the usual hymenopterous type, plump 

 and fat, broad posteriorly, somewhat narrowed towards the head, with 

 strong mandibles. The trachea? are prominent and visible beneath the 

 cuticle under the microscope or even when examined with a hand-lens 

 magnifying at least ten diameters. When full-fed it leaves the host, 

 which lies dead and shrivelled up within the boll or the shoot or on the 

 spot where it was parasitized. Pupation takes place on a leaf, within 

 the shoot or the boll where the host was feeding prior to parasitization. 

 The cocoon is cylindrical, flattened towards both ends. It is dirty 

 white in colour and rather firm in texture. When the adult emerges 



* See paper No. 80 in these Proceedings. 



