W. NOWBLL 40 



The laying female may be seen in the field running quickly over the 

 surface of the soil, her antennae vibrating rapidly all the while. As she 

 obtains the required indication she commences to burrow, shuffling 

 forward with her legs and appearing to use her head to separate the 

 particles of soil. 



Tiphia has never been induced by the writer to take any notice of a 

 grub on the surface, but the method of attack was seen in the case of a 

 half-buried grub and closely resembled that of Campsomeris dorsata, 

 to be described in detail later. Neither Tiphia nor Campsomeris will 

 lay on a grub close to the surface, but after stinging it into quiescence 

 each proceeds to burrow under it and drag it down. The Tiphia 

 mentioned above took several minutes in getting her prey out of sight, 

 during which it recovered activity after the first sting and received a 

 second. 



The egg is laid transversely in a fold of the dorsum of the thorax, 

 and is firmly agglutinated throughout its length by a cement which 

 is colourless at first but eventually becomes dark brown. The egg 

 measures a little over a millimetre in length. It is quite white when 

 first laid but soon darkens slightly. In no case under natural conditions 

 has more than one perfect egg been found on one grub. Occasionally 

 a grub has been found in the field with an egg or larva upon it and in 

 addition to this a brown elongated spot has occurred, apparently 

 marking the position of a previous egg. In the insectary, where the 

 operations of several females were confined to a limited number of 

 grubs in the same flower-pot, such cases were very common and the 

 remains of two eggs in addition to the living one were sometimes found 

 on the same grub. It appears somewhat probable that when a wasp 

 about to deposit her egg finds one already there she destroys it. 



The egg stage occupies 5-6 days. At the end of this time the 

 membrane splits transversely close to one end, which then forms a 

 cap hinged on its dorsal margin. From the opening thus made the 

 head and one or two additional segments of the larva are extruded. 

 While thus situated the larva punctures the skin of the grub with its 

 mandibles. The perforation is very minute and is very little enlarged 

 during the remainder of the life of the host. The head of the larva is 

 'closely applied to the hole, but is not pushed into it and is quite free 

 to move. Whether in feeding there is an actual suction by the larva, 

 or whether the fluid simply wells out from the wound and is imbibed 

 from the surface, was not determined. Continuous movements resem- 

 bling peristalsis may be seen within the body of the parasite. On 



Ann. Biol, n 4 



