Ni^TH Report of the State E^TOMOLOGIST 



327 



tion and illustrations of tbe several stages, methods of preventing its 

 ravagt's, together -with its bibliography and synonymy. 



Whether or not, eggs of the pear-tree Psylla, are, in some cases at 

 least, deposited in the autumn for hibernation, seems still an unsettled 

 question. 



Mr. Slingerland found a hibernating brood of the winged insect, 

 iu both sexes, in the month of December, hidden in crevices under 

 loosened bark of the trunks and larger branches of trees. The 

 females contained no mature eggs. During some warm, days occurring 

 about the 7th of April, hibernated adults were seen in copulation and 

 a few eggs were laid. By April 18th, most of the eggs had been 

 deposited — in crevices of the bark, in old leaf scars, and about the 



bases of terminal buds of the preceding 

 year — usually singly, but sometimes in 

 rows of eight to ten. Under a continu- 

 ance of cold weather, the eggs did not 

 hatch until more than a month thereafter, 

 or May 10th to 18th, but eggs that had 

 been removed and subjected to the 

 warm temperature of the Insectary, gave 

 out their larva? in eleven days. The 

 larvie at once resorted to feeding grounds 

 Avhich were usuall}' found in the axils of 

 -Pupa of the pear tree the leaf petioles or Stems of the young 



Psylla, do; sal view. ^-^.^^j^^ j^^^ ^^^.^j^ ^^^^ ^^^^^^^ ^j^^j^. ^j^^^.^. 



beaks and extract the sap. '"'The whole life-cycle of the generation 

 studied, from the layiug of the egg to the appearance of the adult insect, 

 was about one month " [in the Insectar}']. 

 During this time, five stages — " nymph 

 stages" — of the immature insect were 

 observed, followed by the fifth molt 

 giving the winged adult. [If it be pre- 

 ferred to i-etain a " pupal stage " for the 

 insect, the last two of the above noted 

 may be so regarded, in which there are 

 eight antennal joints, while the preced- 

 ing show but three, four, and six or seven 

 respectively, according to Mr. Slinger- 

 land's observations.] Figures 12 and lO 

 represent the full-grown "nymph" or fig. 13.- Pupa of the pear tree Psylla, 

 pupa — the natural size indicated by the ventral view, 



accompan^'ing hair-lines. 



Fig. 12 



