318 



JboRTY-sixiH Report on the State Museum 



Lintner: in Count. Gent., Ivi, 1891, pp. 317, 374, 637; in Canad. Entomol., 

 xxiii, 1891, p. 230 (in Hudson river valley); in Science, xix, 1893, p. 

 343; 8th Rept. Ins. N. Y., 1893, p. 219. 



Riley-Howard : in Insect Life, iv, 1891, pp. 127-9 (description and habits from 

 Loew), p. 225 (occurrence in New York); id. , v, 1893, p. 200 (is undoubt- 

 edly P. pyricola of Foerster), pp. 226-230 (observations of Mr. Slinger- 

 land, and dimorphism). 



Powell : in Orange County Farmer, May 21, 1891 (brief notice). 



Fisher : in New Engl. Homestead, Dec. 5, 1891; in Bull. No. 17, Hatch Agr. 

 Exp. St., 1892, p. 24 (habits and remedy). 



LODEMAN : in Garden and Forest, v, 1892, p. 285 (brief notice of habits, etc.). 



Slingerland : in Count. Gent., Ivii, 1892, p. 629; in Canad. Entomol., xxiv, 

 1892, p. 207 (injuries, broods, remedy); in Insect Life, v, 1892, pp. 

 100-103 (description, transformations, remedies, etc.); Bull. 14, Cornell 

 Univ. Agr. Exp. St., Oct., 1892, pp. 159-186, 7 figs, (full account). 



-Smith: in Canad. Entomol., xxiv, 1892, p. 207 (copper and London purple 

 spraying for it); Insect Life, vi, 1893, p. 192 (injuries and spread in 

 New Jersey). 



Until within a few years the pear tree has been remarkably free from 

 insect attack — the amount of injury from such source being probably 

 less than five per cent of that to which the apple tree has been subjected. 

 Recently two pests have forced themselves upon the notice of pear- 

 growers, which have already inflicted serious losses, and threaten, unless 

 arrested, greatly to interfere with the cultivation of this most excellent 

 and prized fruit. Of these, the pear midget Diplosis pyrivora (noticed 

 in the preceding Report), which was introduced in this country about 

 the year 1880, has not become broadly distributed, and has not occa- 

 sioned much trouble except in western Connecticut and in portions of 

 the Hudson river valley. 



The pear-tree Psylla is also an introduced insect, which has been with 

 us for a number of years — how long, is not known, 

 but long enough to have carried it into some of our 

 western States. It has, at times, multiplied exceed- 

 ingly in particular localities and become very 

 destructive, as notably in the summer of 1891, in 

 the Hudson river valley, in association with the 

 pear midge. Fortunately, however, after continuing 

 its injuries for a 



Fig. 9.— The pear-tree 

 Psylla, Psylla pyri- 

 cola, male. 



check to its further 



few years, its ex- 

 cessive multipli- 

 cation seems to 



operate as a 

 increase, and to consign it for 

 another term of years to insignifi- 

 cance in numbers and comparative 

 Jiarmlessness. 



Fig. 10— Wings of the pear tree Psylla; c, 

 clavus; c. «., claval suture; s, stigma. 



