iN\'i:sri(iA rioN (H' i.ii' 



II is'i()i;\- 



43 



molted twice in the jais. The moilalily I'oi- th(^ season of 1909 was 

 10 per cent of tlie <S,2<S0 laivje which were fed in this way, and for 

 1910 it readied 12 per cent of the 8,720 larvic tliat hatched. It is 

 interestint; to compare these fi<>:ures A^th tliose for the year 190S wlien 

 a smaller number of larvne was fed individually in jelly «j;lasses 

 provided with cheesedotli covers. A considerable nund)er of lai-vae 

 escaped by fo)cin<2; their way throuf2;h the covers and in all 13,8 per 

 cent of the total for tlie year (2,854) were either lost or died. This 

 shows that the imi)roved covers used on jars the followinji^ years and 

 tlie experience (gained in handlin<^ the larva' have resulted in reducing 

 the moitality. 



Since the work began, July 23, 1907, nearly 20,000 Calosoma 

 larva? have been cared for and most of these have been liberated in 

 the field. 



In August, 1909, a considerable stock of Calosoma larvae was on 

 hand at the laboratory, and as it seemed advisable to feed and carry 

 them through the 

 larval stages and 

 liibernation w here 

 they could be under 

 direct observation 

 they were placed in 

 large box cages (see 

 PI. V) set in the 

 ground . These were 

 2 by 3^ feet in size, 

 and were provided 

 with a fine wire- 

 netting bottom so 

 that the larva3 could 

 not escape. The 

 earth in the cages 

 was 15 inches deep. Several cylinders of galvanized iron wire, 17 

 inches in diameter, were also constructed for the same purpose 

 and were sunk in the ground and later stocked with larvje and food. 

 (See fig. 18.) These cylindeis were lined on the inside with mosquito 

 netting and the tops and bottoms were made of the same mateiial. 



One thousand three hundred and eight second and third stage 

 Calosoma larvjB were placed in these cages or cylinders between July 

 30 and August 27, 1909, and of this number 210 larvae, or 16.6 per 

 cent, were killed ])y their comrades. The food supply was of necessity 

 very poor in quality, especially after the middle of August when 

 gipsy moth larvae and pupae that had been held in cold storage were 

 furnished, many of which w^ere in a l)adly decom])osed condition. 



Fig. 18.— Wire-screen hibernation cylinder where larva; of Calosoma 

 were fed in August, 1910. Photographed February, 1911. (Original. ) 



