54 Tivo Scolild Parasites 



influence of nutrition, would sufficiently account for the relative infre- 

 quency of the smaller sizes of the parasite. The whole question is 

 perhaps worthy of direct investigation. 



The life history of this wasp was worked out during 1912 at Spencers 

 Plantation. Since it had not at that time been found by the writer 

 in connection with Phytalus, the probabilities pointed to Ligyrus as its 

 host, and a search revealed, associated with Ligyrus in pen manure, an 

 abundance of parasitic larvae and cocoons which turned out to be those 

 of Campsomeris. 



When pen manure, containing large numbers of Ligyrus grubs, was 

 being put out in the fields and buried alongside the young clumps of 

 sugar-cane in February 1913, large numbers of the wasps, male and 

 female, were seen in the same fields; the males were darting rapidly 

 about just above the ground, the females were flying from one cane 

 clump to another and alighting to search the surface of the soil over 

 each place where the manure was buried. Many were seen to burrow 

 rapidly out of sight in such situations. They remained below for very 

 various lengths of time, and in most cases digging at the spot where 

 the wasps had burrowed revealed, at a depth of from six inches to a foot, 

 a larva of Ligyrus alive but stupefied and with an egg upon it. 



A healthy larva of Ligyrus was dug up and placed on the surface of 

 the soil near to a hunting female Campsomeris. The latter quickly 

 took notice of it, and a struggle ensued between the two which lasted 

 about five minutes. The wasp, before she would use her sting, 

 manoeuvred for a hold which would enable her to plant it in the right 

 place, which proved to be a spot between the legs of the larva, as near 

 as could be made out between the third pair. Three times when the 

 wasp faced the grub for this purpose some part of her head or its append- 

 ages was seized between the mandibles of the grub. When she finally 

 succeeded in inserting her sting the grub immediately relaxed and 

 became quiet. The wasp then proceeded to burrow under it, and after 

 loosening the soil, she pulled it under. This was about 5.15 in the 

 evening. 



The place was marked and visited early next morning, when the 

 grub was found buried ten inches deep, with an egg upon it. The wasp, 

 in an exhausted condition, was turned up at the same time. There 

 was no manure within several feet of this place, so that it is unlikely 

 that a second grub was mistaken for the first. 



The egg of Campsomeris is attached by one end about the middle of 

 the ventral surface of the grub. It is easily separated and the resulting 



