HABITS OF TWO PARASITES OF BLOW-FLIES. 233 



No signs of Chalcid infestation was observed. The female may- 

 have died within a few days of the start of the experiment. 



The foregoing experiments show that, under certain conditions 

 — and with fractured puparia — JVasonia can super-parasitize 

 A. manducator lined and inhabited puparia, and in two 

 instances three larvso reached full growth. 



Whilst experiment No. 2 was developing, experiments into 

 other directions w ere undertaken. 



It has been previously stated that blow-fiy larvae upon 

 recovering from "temporary paialysis" are stimulated to puj)ate 

 and to escape from the females of A. manducator. It was there- 

 fore decided to ascertain to what depth such larva; worked their 

 way into the soil. 



Experiment iS^o. 3. — A wooden box with a sliding lid was 

 requisitioned. One end was removed, and the sliding lid sawn 

 across into strips an inch wide. Thus when placed upright with 

 the remaining end as the base of the box, the original base 

 formed one side and the sliding lid in strips the other, with the 

 original sides as ends. 



This box was then gradually filled Avith soil which, during the 

 building up of the requisite depth, was twice subjected to riuming 

 water to damp it. Seven inches of soil were eventually put in. 

 On the same day — 9th January, 1920 — pieces of liver upon which 

 fly-larva' had been feeding were placed on the surface of the soil 

 in a compact mass. One female A. manducator was then caught 

 in a tube from the main cage. The mouth of the tube was tlien 

 held over the liver until the female was stimulated to descend 

 upon it. As soon as she got on to it, she started examining it for 

 larvte. 25 of these, about three-quarters to full grown, Avere at 

 hand ; they Avere placed near the female, one at a time, so soon 

 as she had oviposited into each of them. In three instances she 

 attacked twice, having failed to come in contact Avith the sub- 

 stitutes, and in each case the latter Avere Avithdrav,^n and given 

 to her a second time. It took 57 minutes to get the 25 larvje 

 parasitized. The female Avas moved back into the tube and 

 given a smear of food on the cork. She Avns alloAved to rest in 

 the tube for 20 minutes. In the meauAvhile another 25 larvfe 

 had been collected. The female Avas noAv released again, and the 

 same pi-ocess started, but she only attacked one of these larA^a? ; 

 and although others Avere placed near her, she could not be 

 induced to attack any more, and after 26 minutes the experi- 

 ment Avas given up for the day. The remaining 24 larvfe of the 

 second lot were returned to their breeding dish, and the female 

 caught and left in the tube Avith food. 



No further action Avas taken for the next tAvo days. On 12th 

 January, 1920, the experiment A\-as continued. The above female 

 Avas found dying ; another Avas therefore removed from the cage, 

 and at 2.30 p.m. it Avas set to work on 25 larvpe as before, but 

 at 3.25 P.M. it suddenly became dark, and the female refused to 

 oviposit any more. In this time — 55 minutes — she had dealt with 



