13 



ished upon twigs upon which the scales were closely massed together, 

 and ate its way through the mass from one scale to another, spinning a 

 close, rather dense web as it progressed. Each caterpillar in this way 

 destroyed very many scale insects. The writer has always thought that 

 it was due to this insect alone that the cottony cushion scale almost 

 disappeared from the Washington shade trees in the close of 1870, and 

 was never seen here again in any great abundance until, in the summer 

 of 1898, nineteen years later, it became once more rather conspicuous, 

 although by no means as abundant as in the former year. TheDakrnma 

 larva not only destroys the old and worn-out female Pulviuaria but 

 devours her eggs and young larvae with avidity. The caterpillars are 

 very active, moving about freely within their silken i>assages. They 

 were found to be full grown on June 21, spun their cocoons within the 

 silken tunnel, and remained ten days in the pupal state. The moths 

 issued from July 17 to August 13, soon thereafter ovipositing and lay- 



ITig.7. — Pulviuaria innumorabilis: «, adult male; b, antenna of same ; c, leg of same; d, second stage 

 of pupa; e, cast skin of same; /, true pupa; g, cast skin of same— all greatly enlarged, b and c still 

 more enlarged (original) . 



ing their eggs, which hatched in six days. Whether another generation 

 of moths issues the same year has not been determined. 



An even more important enemy of the cottony maple scale than the 

 Dakruma larva or the ladybirds just mentioned is a minute Chalcidid 

 fly known as Coccophagus lecauii (Fitch). This species, which has been 

 reared from a number of different scale insects of the Lecanine group, 

 is very widespread and appears frequently in astonishing numbers. 

 It was due to this parasite that it was found almost impossible to carry 

 the scale insects through the season at Washington in 1898; of the 

 many thousands of scale insect larvae which settled upon trees under 

 observation it is sate to say that much less than 1 per cent reached 



