NOTES AND OBSERVATIONS. 315 



'IQ. A. Berlbse : " Importanza nella economia agraria degli 

 insefcti eudofagi distruttori degli Insetti nocivi," Boll. Scuola 

 Agric. Porfcici (2)4, pp. 1-27, 1902. Berlese discusses the im- 

 portance of such predatory insects as the Coccinella, Cochylis, 

 Pteromalus, &c., in checking the ravages of insects injurious to 

 crops, &c. 



27. N. Gholodkovsky : " Ueber den Hermaphroditismus bei 

 Chermes-Arten," Zool. Anz., 1902, pp. 521-2, three text figs. 

 [Rhynch.] Hermaphroditism discussed in certain Aphidse. 



28. A. Porta : " Ricerche sull' apparato di secrezione e sul 

 secreto della Coccinella 7-punctata, L." [Col.] 



29. 0. ScHULTZ : " Varietaten und Aberrationen von Papilio 

 podalirius, L., uebersicht liber die Variabilitat dieser species " 

 [Lep.] , Berl. Ent. Zeit. 47, pp. 117-33, 1902. 



30. J. B. Smith: ''Report of the Ent. Dept. of N. Jersey 

 Agric. Exp. Sta. for 1902 " ; 1903, pp. i-iv and 423-593, 16 figs, 

 (many full or double page). This is of the usual type of Dr. 

 Smith's well-known Reports, being largely occupied by a detailed 

 account of his mosquito experiments. 



31. S. A. Forbes : " Twenty-second Report of the State 

 Entom., Illinois"; 1903, pp. i-viii, 1-149 and i-xx, 33 figs, 

 (many full page). This valuable Report is largely taken up 

 with discussion of field work against the San Jose scale, and 

 notices of the " Corn Bill-bugs" {Sphenoplwrus spp.), a genus of 

 Rhynchophorous Coleoptera. 



32. K. EscHERicH : " Beitrage zur Kenntniss der Thysa- 

 nuren," Zool. Anzeiger, 14th Apl., 1903, pp. 345-66, twelve 

 text figs. A valuable contribution to our knowledge of certain 

 Thysanura. 



NOTES AND OBSERVATIONS. 



Abundance of Pyrameis cardui. — The occurrence in England of 

 large swarms of P. cardui may be due, as Mr. Mathew suggests, to a 

 prevalence of easterly gales which drive them across from Norway, 

 Denmark, or France. But it will generally be found, I think, that 

 when this species is exceptionally abundant in England, it is equally 

 so on the Continent ; and it is possible that the same mysterious pro- 

 creative agencies may be at work in both cases. This is, I suppose, 

 what may be called a cardui year, for my garden here is alive with 

 them all day long, and on the heliotrope, covering a piece of wall ten 

 yards long by eight feet high, I saw at 11 o'clock on the morning of 

 Nov. 6th, at a moderate computation, between seventy and eighty at 

 one time, the majority rather worn, but many quite fresh. The 

 appearance of vast multitudes of certain species at irregular intervals 

 is a problem still awaiting solution. I remember a year — '81 I think 

 — when Plusia gamma lay so thick for a mile or more along the beach 

 at Cromer that it was impossible to move without stepping on them. 

 It has been suggested that many pupse lie over and accumulate from 



2 c 2 



