NATURAL CHECKS OF COTTONY MAPLE SCALE. 4'* 



was the larva of Dakruma coccidivora Comst. Some of the enei. 



however, appear to be found wherever the scale occurs, and prominent 

 among these are the parasite Goccophagus lecanii Fitch and the coc- 

 cinellid beetle Hyperaspis signata Oliv. and its larva. It has been 

 due largely to these species that the scale has been controlled in New 

 Jersey during the past two years. 



In 1004 Pulvinaria innumerabUis was noted rather plentifully in 

 several places in Newark and near-by towns and at New Brunswick, 

 and the indications were that it would be much more plentiful the 

 following season. Our anticipations were realized, and in 1905 the 

 scale occurred more abundantly than it had for several years. In 

 order to watch its development the infested districts were visited from 

 time to time and the condition of the insects and the trees noted. 

 As the year progressed it was observed that the enemies previously 

 mentioned were materially and effectively checking the scale, and it 

 was predicted that the number of the insects would be considerably 

 reduced and in some localities nearly exterminated in 1900. These 

 predictions were likewise fulfilled: and in Montclair, where some of 

 the worst infested districts occurred in 1905. there has been very little 

 evidence of the Pulvinaria during the past year. 



The first signs of parasitism were observed in the middle of April, 

 after the fertilized female scales had started to develop. "While most 

 of the insects at that time were becoming enlarged, a few were 

 observed to be quite convex, and an examination showed that they 

 were infested with parasitic larvae, a few of which were full grown. 

 Only a single larva occurred in each of the scale-, which were light 

 in color at this time, but as the larvae pupated the parasitized scales 

 became dark and hard. From this time on the number of the latter 

 increased, and by the middle of May two and one-half times as many 

 parasitized as good scales could be observed on some of the leave-. 



The adult parasites were first observed about the middle of May 

 and continued in increasing numbers until early June, after which 

 they began to decrease, and were last observed about the middle of 

 that month. Examples were sent to Dr. William II. Ashmead, who 

 determined them as Coccophagus lecanii Fitch. Whether this para- 

 site hibernates as a larva or in the egg stage I am unaware. It is 

 apparent, however, that the larva begins to develop some time in 

 early April, and the species continue- in evidence for a couple of 

 month-. In emerging it cuts an irregularly rounded hole in the dor- 

 sal surface of the scale, and. so far as I could observe, it was always 

 nearest the posterior end. 



Thus the parasites had destroyed many of the hibernating female-, 

 but the number of the latter which went into hibernation was so large 



T 187 — No. <!T — 07 i 



