XXXli, '21] ENTOMOLOGICAL NEWS 85 



BIOLOGY. 



In rearing the immature forms, glass vials with cotton 

 >t uppers were used and when records of the length of instars 

 were desired the food given was rose mildew (Sphaerotheca 

 pannosa). 



Between September 12 and 30, 1918, a female deposited 110 

 ova, or 6 per day: another deposited 106 ova between Sep- 

 tember 10 and October 4, 1918, or 4.2 per day. The largest 

 number deposited in a single day by an individual was 14, each 

 female on one occasion reaching this amount. During the 

 egg-laving period the beetles fed on rose mildew. The adult 

 female commences oviposition about ten days after emergence. 



Out of a total of 74 eggs under observation during August 

 and September, 1918, all but two hatched. Field observations 

 also indicate that very few eggs of this species are infertile. 



TABLE 1. 

 Incubation periods of 14 clusters of cyys during 1918; 



Sacramento, Calif. 



Number Date of Date of Incubation 



(.Muster No. of Eggs Deposition Hatching Period (Days) 



1 10 July 17 July 22 5 



2 2 Aug. 25 Aug. 30 



3 17 Aug. 29 Sept. 3 



4 8 Aug. 30 Sept. 4 . 



5 6 Aug. 31 Sept. 5 



6 2 Sept. 18 Sept. 27 9 



7 4 Sept. 18 Sept. 26 8 



8 Sept 19 Sept. 28 9 



9 9 Sept. 20 Sept. 28 8 

 1(1 5 Sept. 20 Sept. 29 9 



11 3 Sept. 21 Sept. 29 8 



12 13 Sept. 21 Oct. 1 10 



13 18 Sept. 25 Oct. 2 



14 3 Sept. 26 Oct. 3 



From Table 1, it is seen that the minimum incubation period 

 at the warmest part of the year is about 5 days and that in 

 the second half of September around the autumnal equinox 

 it is increased to about 8J/2 days. 



In the field the eggs are always placed close by a fungus 

 infestation so that newly hatched larvae find a food supply 

 at hand. All through their larval existence the insects under 

 olcr\ ation fed on the fungi ; when the mycelial filaments were 

 thick the insects cut semicircular swaths through them. M>me- 

 what reminiscent of the manner of feeding of certain lepidop- 

 terous and saw-fly larvae on leaves. 



