139 



should be continued for about 10 days during each cycle. The formula 

 recommended is anhydrous sodium arsenate, 14 oz. ; lead acetate in 

 crystals, 2| lb. ; water, 20 gals. The acetate must be dissolved 

 separately in 2 gals, of water and added slowly to the sodium arsenate, 

 which has also been dissolved in 2 gals, of water ; this must never be 

 done in the reverse order. The quantity of lead acetate required 

 differs according to the temperature of the water and other materials 

 and should be determined exactly by an indicator paper, prepared by 

 submerging slips of unsized paper in a 10 per cent, solution of potassium 

 iodide and allowing them to dry. When the paper turns yellow, there 

 is sufficient acetate present. This spray should never be used later 

 than August. 



Philanthos ( — ). II nielo {Pyrus mains, L.). [The Apple Tree.] — 

 Riv. Agric, Parma, xxii, no. 51, 22nd December 1916, pp. 778-779. 



The usual controls for Eriosoma lanigerum are advised, including the 

 aj)plication of a commercial oil varnish consisting of a mixture of 75 

 parts of linseed oil, 15 of white lead, and 10 of zinc oxide, which is 

 boiled for 10 minutes, and, after it has cooled, has 10 parts of turpentine 

 spirit added to it. 



NiNiNGER (H. H.). Studies in the Life-Histories of two Carpenter Bees 

 of California, with Notes on certain Parasites. — J I. Eniom. and 

 Zool., Claremont, Cal., viii, no. 4, December 1916, pp. 158-166, 

 2 plates. 



Xylocopa orpifex, Smith, was kept under systematic observation for 

 a period of one year from 29th September 1915. The colony chosen 

 for study was situated at an altitude of 3,500 feet at the top of a small 

 mountain. This insect shows a decided preference for redwood 

 (Sequoia), but has been found on one or two occasions in Oregon pine. 

 It is always found in sound wood, showing no inclination for decaying 

 timber. Its method of boring into the timber is described, as well as 

 its life-history. It is parasitised by the Bombyliid, Spongostylum 

 delila, Lw., which is found as a very minute, but exceedingly active, 

 larva on the food-mass prepared by the female bee and on which it lays 

 its egg. Other parasites of H. orpifex are a Phycitid moth and a 

 Tenebrionid beetle {Ajihanotus brevicornis, Lee). Mites of the genus 

 Trichotarsus infested a few nests and in some cases destroyed developing 

 bees, though the emerging adult often carried them away among the 

 hairs covering the thorax and seemed to be uninjured. 



Xylocojja varipiincta, Patton, is larger than X. orpifex. It inhabits 

 the valleys and lower hill regions. It seems to prefer partly decayed 

 wood, and is found most abundantly on live oak, pepper and eucalyptus 

 trees. In making its tunnels it follows the grain of the wood, while 

 X. orpifex makes perfectly straight tunnels irrespective of the course 

 of the grain. The only parasite of this bee found was the Trichotarsus 

 mite, which destroyed a small percentage of larvae. 



X. orpifex occurs from Arizona and Nevada southwards to Lower 

 California, andX. varipiincta in Texas, Arizona, and Lower California, 

 but not in New Mexico. 



