760 



the poisoned caterpillars, the bodies were first dried at 212° F. to get 

 the actual weight of the dry tissue of the insects, and this was then 

 chemically analysed. From the tables given, it appears that the 

 arsenic content of the caterpillars poisoned with the lead hydrogen 

 arsenate was somewhat the greater. This may be due to the higher 

 arsenic content of the compound or to a more rapid absorbtion of this 

 substance into the tissues. 



Clausen (C. P.). A Comparative Study of a Series of Aphid-Feeding 

 Coccinellidae.— JZ. Econ.Ento)»., Concord., viii, no. 5, pp. 487-491. 



In order to determine the relative efficiency of some of the more 

 important forms of Coccinellidae, a study of eight of the principal 

 Aphid-feeding species of California was made at Sacramento during 

 1913, and completed at Berkeley and Riverside in 1914. The species 

 under observation were Hippodamia convergens, Guer., H. ambigua, 

 Lee, CoccineUa calif ornica, Mann., C. trifasciata, L., Olla oculata, F., 

 0. abdominalis, Say, Cycloneda sanguinea, L., and Adalia bipnnctata, L. 

 Very extensive tests showed that the most satisfactory type of breeding 

 cage was a plain three-inch vial with a cotton stopper. The stopper 

 was covered with tissue paper to prevent the larvae from becoming 

 entangled in the cottony fibres. No great divergence was found to 

 exist between species as regards the length of time intervening between 

 emergence and mating. The period of time over which oviposition 

 extends is very largely dependent upon the conditions under which 

 the beetles are kept. Under optimum conditions the deposition of 

 eggs takes place daily from approximately two weeks after emergence 

 until death. Oviposition by one female of H. amhigtia extended over 

 59 days. A very considerable difference was found to exist in the 

 number of eggs deposited by the various species ; H. convergens 

 deposited the greatest number and A. hijnmctata the least. The totals 

 of the successive stages of the life-history gave a minimum of 21 

 days for 0. abdominalis and a maximum of 32 '2 days for H. ambigua. 

 The feeding records show that the average number of Aphids eaten 

 by a larva during the entire period ranged from 216 for C. sanguinea, 

 to 475 in the case of C. californica. One individual of the former 

 species came to maturity after consuming 147 Aphids, while one larva 

 of C. californica required 580, this being the maximum for a single 

 individual. In the case of the adult beetles, the average numbers 

 ranged from 624 Aphids for 0. oculata to 234 for C. sanguinea. 

 One adult of 0. oculata devoui-ed 672 Aphids. On a daily basis, the 

 variation extended from 56*1 Aphids per individual for H. convergens 

 to 15"6 for C. sanguinea. C. californica was conspicuously low in this 

 respect when the size of this beetle is considered, the average being 

 only 34 Aphids a day. 



WoLcoTT (G. N.). The Influence of Rainfall and the Non-Burning of 

 Trash on the Abundance of Diatraea saccharalis. (Abstract). — 



JI. Econ. Entom., Concord, viii, no. 5, October 1915, pp. 496-498. 



The abundance of Diatraea saccharalis (smaller moth borer), the 

 most important pest of sugar-cane in the New World, depends upon 

 two factors, rainfall and the burning of trash. Rainfall cannot be 



