ECONOMIC ZOOLOGY ENTOMOLOGY. 649 



birds. The species of iusects ami otber auiiual aud vegetable substances takeu 

 from the stoinacbs of a large nuniber of individuals have lieen identified and 

 are listed for each of these species. 



Summariziui; the. results of studies of the common robin {PUtncHiicu^ iniyra- 

 lorius and subspecies), the author concludes that while in all probability it is 

 to-day doing much more good than harm it must be acknowledged, that the bird 

 is potentially harmful since its diet contains a large percentage of fruit, in- 

 cluding many varieties. Investigations of the varied thrush, or Oregon robin 

 (fj'oreus tKevius and subspecies) indicate that it is not likely to do much mis- 

 chief by eating useful insects since a good proportion of its animal food consists 

 of such as are of no economic significance. Since this bird does not at present 

 spend the breeding season in a well settleil and cultivated country farm prod- 

 ucts are not fed tipon. The eastern bluebird {Hlalia sialis and subspecies) 

 does not prey upon any product of husbandry or in any way render itself in 

 jurious or annoying. During the spring and early summer when small fruits 

 are at their best It subsists on insects to the extent of five-sixths of its food, 

 and during the late fall and early spriug when insects are scarce only waste 

 fruit is available. The western bluebird (&'. mexieana subspecies) is found to 

 he an eminently useful species. The mountain bluebird (S. currucoides) has 

 probably not yet come in contact with the products of husbandry extensively 

 enough to demonstrate its real propensities, but the nature of its food does not 

 iudicate tliat there is much to be feared from it. 



Quassiin as a contact insecticide, W. B. Paekee {U. S. Dept. Agr. Bill. 165 

 (1914), PP- 8, fig. 1). — Quassia wood (Picrasma excelsa), a native of Jamaica 

 that is available in considerable quantities, has for many years been employed 

 In the preperatiou of spray solutions for the control of the hop aphis (Phorodoti 

 Jiumuli). The percentage present of quassiin, the active principal in the chips, 

 varies somewhat and does not appear to be definitely known. If the percentage 

 be 0.75, as given by one author, in order to use it at an effective rate of 0.4 

 gm. to 2,000 cc, only 1.5 lbs. of chips to 100 gal. of spray would be required. 

 The author states that if twice the amount of chips calculated to be necessary 

 were used, in order to be on the safe side, and 3 lbs. of whale-oil soap added, 

 the cost of material for 100 gal. of the spray would amount to but 24 cts. 



In an attempt to determine its iusecticidal value the author compared the 

 ac-tion of quassin with that of a standard contact insecticide, namely, nicotin 

 sulphate solution, standardized to 40 per cent, and used at the rate of 1 : 2.000. 

 Since whale-oil soap even at the greatest dilution at which it has any spread- 

 ing effect was found to kill a certain percentage of aphidids, a soap bark' solu- 

 tion was used at the rate of 2 lbs. to 100 gal. of water. In conducting the ex- 

 periments prune twigs infested by the hop aphis (P. humuli) and the prune 

 aphis ( Ryalopterus pruni) were brought from the field and after being sprayed 

 with the solutions were set in moist sand. The results presented in tabular 

 form show that " quassiin used at the rate of 0.4 gm. to 2,000 cc, or 6.5 oz. of 

 40 per cent solution to 100 gal., was almost as efi'ective against the hop aphis 

 and the prune aphis as nicotin suli)hate, 0.4 gm. to 2,000 cc. The difference is 

 approximately 3 per cent, while quassiin, 0.4 gm. to 1,000 cc, is fully as ef- 

 fective." 



The author is of tlie opinion that quassiin has possibilities as a commercial 

 insecticide and that it can be cheaply prepared and profitably sold at a lower 

 price than some of the materials that are now on the market. It is pointed out, 

 however, that the exi»eriments were conducted under conditions existing at 

 Sacramento, Cal., and that the etficacy of this insecticide should be determined 

 alsa for a more humid climate before a commercial recommeudatiou is made, 



