60 EXPERIMENT STATION RECORD. [Vol.43 



in the rapid and virulent manner common in Isle of Wight disease, although at 

 the same time we are satisfied that Nosema-affected stocks do not yield the 

 same amount of stores as iiealtiiy colonies." 



A synopsis of the petiolate wasps of the family Eumenida* (Hymenop- 

 tera) , found in America north of Mexico, D. Isely (Ann. Ent. Soc. Aincr., 10 

 (VJll), No. Jfy pp. S45-.366). — This is a synopsis of the genera Eumenes and 

 Zethus. The author recognizes 22 forms of Eumenes, 9 of which are new, and 

 5 of Zethus. 



Viereck's family Labenidae with the description of a new^ species of 

 Apechoneura, R. A. Cushman {Proc. Ent. Soc. Wash., 22 (1920), Xo. 4, pp. 76- 

 80, fl(j. 1). 



Parthenogenesis in the pear-slug sawfly [California cerasi Linn.], H. E. 

 EwiNG (Ami. Ent. Soc. Amer., 10 (1917), No. 4, pp. 530-536).— " The males of 

 our conunon pear- or cherry-slug sawfly must be very rare in certain parts of 

 our country. The examination of several hundreds of individuals obtained at 

 various times during the late spring and summer for three seasons at Ames, 

 Iowa, and for two seasons at Corvallis, Oreg., failed to reveal a single male. 

 The species is parthenogenetic, and successfully so for the offspring of the 

 spring brood of females. The eggs deposited by spring-brood virgin females 

 hatch and produce normal vigorous larvse. These feed normally, later pupate, 

 and finally produce adults. Unfertilized eggs produce females only. 



" Parthenogenesi.s, when continued for the offspring of the second or summer 

 brood of adults, gave larvje, a considerable percentage of which failed to pupate. 

 A considerable percentage successfully pupated but did not transform into the 

 adult stage, and a very large percentage transformed into adult stage but did 

 not emerge from the inclosing earthen cells. Only a single adult was reared 

 from 109 of tlie second generation parthenogenetic larvse. An orchard which 

 was heavily infested with spring brood females, and in which no males were 

 observed, produced an enormous number of second generation females, which 

 produced in turn an increasing number of second brood larvse, causing injury 

 so .serious as to kill outright several cherry trees of the oi'chard and to seriously 

 injure all of the trees. From this enormous second brood of larvje only a very 

 few adults emerged the following .spring. 



" I am unable to account for the failure of these second brood larvse to pro- 

 duce active adults unless it be on account of a lack of vigor due to the ab.sence 

 of fertilization for this brood, yet it is po.ssible that this failure was due to 

 other cau.ses." 



Studies on Rocky Mountain spotted fever, S. B. Wolbach (Jour. Med. 

 Research, 41 (1919), No. 1, pp. 197, pis. 21, figs. 15). — This is a monographic ac- 

 count of Rocky Mountain spotted fever, a disease of man, transmitted by Der- 

 viacentor venustiis Banks. It includes a detailed report of the author's investi- 

 gations, which have led him to conclude that a microorganism, for which the 

 name Dermacentroxcnus rickettsi is proposed, is the causative agent. Reasons 

 are presented for the conclusion that this organism is not a bacterium in the 

 ordinary sense of the term. Its classification with the protozoa also presents 

 difficulties, due chiefly to its minute size. 



A list is given of 97 references to the literature. 



FOODS— HUMAN NUTRITION. 



The nation's food, R. Pearl (I'hiladelphia and London: W. B. Saunders Co., 

 1920, pp. 274, fiijs. //2). — This l)ook, which is the outcome of the author's work 

 as chief of the statistical division of the U. S. Food Administration from June, 

 1917, to March, 1919, consists of an exhaustive statistical survey of the food 



