523 



Preliminary tests with a variety of sugar-cane said to be practically 

 immune from attack by Rhabdocnemis obscura, Boisd., have given 

 encouraging results. As a result of experiments with the Tachinid 

 parasite [Ceromasia sphenophori], December appears a good month for 

 its liberation, as the second brood has time to develop before the onset 

 ■of the wet season and before the appearance of the fungus infesting 

 this fly [Einpusa]. 



Jarvis (E.). Science Notes. — Queensland Agric. JL, Brisbane, xviii, 

 pt. 1, July 1922, pp. 39-45, 1 plate. 



In the Cairns district the larval stage of Lepidoderma albohirtum, 

 Waterh., occurs from February to July ; Lepidiota rothei, Blackb., 

 from March to August ; L. frenchi, Blackb., L. caudata, Blackb., and 

 Anoplognathus boisdnvali, Boisd., at all times ; and Dasygnathns 

 ■australis dejeani, Macl., from January to May. 



Scarabaeid larvae nearing the end of the second instar appear to be 

 readily attacked by Campsomeris, and the readiness of these Scoliids 

 to oviposit on hosts whether large or small would add greatly to their 

 usefulness in other countries into which they might be introduced 

 against root-eating Scarabaeid larvae. Contrary to former experiments 

 it was found that Campsomeris radula, F., will often parasitise larvae of 

 D. australis dejeani. 



The author believes that under natural conditions both C. radula and 

 C. tasmaniensis , Sauss., usually oviposit on larvae of the first suitable 

 host they may encounter. In view of the continuous food supply 

 furnished by various root-eating Scarabaeids and the fact that 73° F. 

 is the average temperature during autumn and winter, Campsomeris spp. 

 can produce successive generations about every three months. The 

 first brood is derived from eggs laid at the end of September. Egg- 

 laying is general towards the end of October and continuous into 

 November. The adults from this brood emerge about the middle of 

 December into January. The life-cycle occupies about 47 days, the 

 duration of the egg, larval and intra-cocoon stages being 3, 8 and 36 

 days respectively. The approximate period occupied by the second 

 brood is from the middle of December to the middle of February. From 

 data compiled in 1917-18 the average durations of the egg and larval 

 stages of this brood of C. tasmaniensis are 3| and 1\ days respectively. 

 The intra-cocoon stage occupies 36 days for the male and 38| days for 

 the female. Temperature and humidity appear to play an important 

 part in this brood. Eggs of the third or autumn brood are laid in 

 March and give rise to adults from May onwards. Eggs giving rise 

 to the winter brood are laid in June or July. These require from 7 

 to 10 days to hatch during winter, while the period occupied by both 

 the egg and larval stages varies from 18 to 24 days at an average 

 shade temperature of 68° F. These stages of the summer brood 

 occupy only 12 days at a temperature of 82° F. These four broods 

 together represent a period of about 270 days, which extended over 

 twelve months gives an interval of 30 days between the broods. 



The eggs of C. tasmaniensis and C. radula are placed singly in the 

 mid-ventral area of the third or fourth abdominal segments of the host 

 larvae. Wlierr two parasites are forced to feed on one host their larval 

 period is shortened, cocoons being spun at the end of six days. Five 

 eggs artificially gummed to the body of one host matured except one, 

 which was on the anal segment so that the larva died after having 



