228 



Fsylla simulans is iu Europe a summer form. Dr. Franz Low* dis- 

 tinctly states: ''The imagines were found in summer on these plants" 



[Fyrus mains and P. commu- 

 nis]', and at another placet 

 he states that the specimens 

 were found by himself: '' I 

 found this si^ecies hitherto 

 only on the apple tree in com- 

 pany with Fs. pyricola.''^ Mr. 

 John Scott I says of his Fs. 

 pyri {=simidans): ''It lives 

 on pear trees, and is to be 



Tig. 28.— Psylla pyricola: a, head of adult, front view; 

 c, cones of clypens; o, ocelli; 6, antenna of adnlt — all 

 enlarged (after Slingerlaud). 



but this is apparently not based on actual observation, and probably 

 taken from Curtis's account of Fsylla pyri {—pyricola). Finally, it is 

 more than probable that hibernating specimens of Fs. pyricola have 

 been collected and examined by authorities in Europe. Dr. Fr. Low 

 would scarcely have made the statement regarding the hibernation of 

 this species without having seen specimens found in winter time.§ 



There is plainly an error somewhere and the following explanations 

 suggest themselves: (1) Either Mr. Slingerlaud may have been dealing 

 with two distinct species occurring at 

 the same time on his trees; or (2) we 

 have been mistaken in the identifica- 

 tion of the winter form as simulans (the 

 determination was made from a study 

 of descriptions and not from compari. 

 son of specimens) 5 or (3) the European 

 observations are faulty ', or (4) the hiber- 

 nating form in central Europe extends 

 into summer. We feel confidence in Mr. 

 Slingerland's views, and shall expect 

 the final explanation to justify them. 



The various life-habits of both the adolescent and adult stages of 

 the insect are more or less fully dealt with by Mr. Slingerlaud, and of 

 the many interesting and novel observations we select here for quota- 

 tion those made on the honey-dew : 



Many have supposed tliat the lioney-dew, so conspicuous a feature in severe at- 

 tacks of this pest, is the sap of the tree Tvhich exudes through the punctures made 

 by the insects. As the honey-dew occurs in such immense quantities it does seem 

 almost impossible that it is wholly the secretion of the little creatures. All of this 

 fluid doeS; however, first pass through the body of the insect. The amount which a 



*Uebersicht d. Psyll. von Oesterreich-Uugarn, etc., 1888, p. 15. 

 tNeue Beitrage, etc., 1886, p. 157. 

 tTrans. Ent. Soc, London, 1876, p. 537. 



^In his Revision d. xialaarct. Psyll., 1882, p. 232, Dr. Low seems to be inclined to 

 consider Ps. argyrostigma Forst. as the winter form oi Fs. simulans. 



Fig. 29.— Psylla 2)yricola: venation of winga ; 

 s, stigma; c, clavas; cs, clavalsntiire — en- 

 larged (after Slingerland) . 



