102 PROCEEDINGS OP THE ROYAL SOCIETY OP QUEENSLAND. 



in its third instar are quite different, being much sharper 

 piercing structures, transversely arranged (fig. 33). The fully 

 grown larva varies in length from 1-3 to 2-4 mm. 



Feeding takes place by the suctoiial action of the mouth 

 applied to the original puncture. Two sets of larval muscles 

 appear to take part in this, a sphincter set surrounding the end 

 of the head and evidently serving to protrude the pharynx, 

 and a retractor set inserted into the pharynx and serving to 

 Avithdraw it (fig. 32). During the feeding stage the intestine 

 remains closed distally. The larva then undergoes a resting 

 period (propupal stage) at the end of which it empties the 

 intestine, the larva (fig. 21) changing from dirty grey to 

 pure Avhite. After about 22 hours it moidts, and a whitish pupa 

 appears, about 1^ mm. in length (fig. 22). About two days later 

 the eyes turn reddish, on the next day they are bright red ; 

 on the following day the anterior half of the pupa turns black, 

 and on the last day the mature wasp ma}^ be seen, within the 

 pupal skin. The whole pupal period lasts about six days in 

 Brisbane (five in N.S.W. according to Froggatt and McCarthy). 

 Altson states that in London the period of development of the 

 larva occupies 7 to 10 days from the time of hatcliing, with a 

 propuj)al stage of 1 to 3 days, the pupal stage being 8 to 12 

 days (1920, pp. 219, 220). Girault and Sanders give 9 days 

 as an average (U.S.A., springtime). 



The males generally hatch first and can be seen on or 

 near the fly-pupa, waiting for the females to emerge. Fertihsa- 

 tion take^ place immediately, and in about six hours (3 to 2-1. 

 Girault and Sanders) the females are ready for laying. 

 Unfertilised females also oviposit quite readily, the offspring: 

 being entirely males. The females will oviposit for about 

 three wrecks. Observations by Girault and Sanders and by 

 Froggatt and McCarthy show that on an average one female 

 may deposit 113 eggs, but unfortunately she distributes them 

 only amongst 17 to 20 ]ni]jJB (on an average) so that her destruc- 

 tive action is considerabh* limited. The wasp thrives fairly A\ell 

 in the Australian climate, and has established itself over wide 

 areas of N.S.W. and Queensland. Froggatt and McCarthy 

 (1914) mentioned the following blowflies as hosts : — Calliphom 

 villosa (= Neopollenia -sft/gia), C. oceanin? (= ParacallipJiora 

 augur), C. eriifhrocephaJa, and C. ruffacies. J. L. Froggatt 

 (1919) added to the list Lucilia sericata, Sarcophaga aurijrons, 

 Ophyrn nigra, and Pi/cnosoma van'pes, the last-named two being 



