18 THE EEPOST OF THE No. 36 



of or in spite of the inclement season. In this vicinity, from about May 10th to the 

 present date, September 33rd, the Red Admiral biitterfiy {Pyrameis atalanta, Lin- 

 nfeus) has been iiniisually plentifiil. It has not appeared in nearly such large 

 numbers since the year 1905. A number of specimens were examined during May, 

 and practically all of them were brightly coloured, and seemed to have recently 

 emerged from the chrysalids. In co]nparison, only a few were doubtfully classed 

 as hibernating forms. No doubt many factors, few of which are yet understood, 

 control the production of each species of butterfly, but in all probability parasitism 

 plays the chief role. This will account for a season with numbers above the average 

 being succeeded hy one with correspondingly low numbers in the same species, the 

 year of plenty having produced ideal conditions for the increase of the parasites. 

 During the season fewer specimens than usual were seen of the other species of 

 butterflies, with perhaps the exception of the Viceroy {Basilarcliia archippus, 

 Cramer). 



The " Spittle Insects," Earn. Cercopidae, were also very numerous. During 

 July, in low-lying land, nearly every specimen of Eed Top {Agrostis alba var. vul- 

 garis, Thurb.) carried a mass of froth, indicating the presence of either the larva 

 or pupa of the insect. With the purpose of testing the froth for the enzyme diastase, 

 a large number of the masses were washed off into distilled water. The froth 

 remained separate from the water until toluol was added; this seemed to alter the 



Fig. 11. — Grape Vine Leaf-hopiper. 



surface tension, and the froth passed into solution. A small quantity of this solution 

 was then placed in about an equal amount of starch paste, made of cornmeal, and 

 left for a few hours. A test with Eehling's solution then showed that a compara- 

 tively large amount of the starch had been changed to sugar. Without further 

 investigation it is rather premature to surmise the purpose of this sugar-producing 

 enzyme, but it seems possible that it may have a pre-digestive effect on the starch 

 of the host and thus convert it into a more soluble form for the use of the larva. 

 Experiments, not yet complete, seem to indicate that stems, surrounded by the froth 

 masses, do contain more sifgar than an equal weight of unaffected stems. 



Another species in the same family also appears to have been influenced favour- 

 ably by the vagaries of the season. Dr. Walker has informed me that the Grape 

 Vine Leaf-hopper (TypMocyha comes) was very plentiful on the Boston Ivy 

 (Ampelopsis veitchii). The leaves on which the insects were feeding had become 

 pale and blotchy in appearance. 



The Elm Bark Louse (Gossyparia spuria, Mod.) has not proven as serious a 

 pest here as was apprehended on its first appearance. It now seems to be practi- 

 cally absent from certain streets, the trees of which were badly infested a couple of 

 years ago. While it has killed some very small introduced elms, it has not injured 

 the larger specimens materially, and the indigenous Ulmus americana, L., is not 

 often attacked by it. Specimens of the Coccid (Kermes puhescens, Bogue) were 

 not numerous this season. This insect causes a marked swelling and distortion of 



