OF WASHINGTON. 67 



indicate that it is viviparous and hibernates in the mature female 

 form. The most interesting fact connected with it, however, is 

 that the very severe and exceptional cold of last winter seems to 

 have killed it out, as, so far, Messrs. Pergande, Schwarx, and 

 Chittenden, who have examined the subject for me, report that 

 they have found no living specimens. 



In this connection I may also give a little experience with 

 Chionaspis furfurus, the well-known Scurfy Scale of Pyrus 

 trees. This proved in my own garden extremely fatal to a hedge 

 of Pyrus japonica, when allowed to multiply, and experiments 

 with kerosene emulsion only 1 diluted showed that comparatively 

 few of the perfect scales in autumn or winter, while the leaves 

 are off the plant, are destroyed by it. It becomes necessary, 

 therefore, to attack it in the young or newly hatched larva state. 

 Fortunately the larvae hatch quite uniformly about the middle of 

 May, and the kerosene emulsion diluted in =; times its bulk of 

 water proved, when carefully applied, thoroughly effectual, 

 without any injury to the plants. Where, however, it was re 

 peated two or three times upon the same plant it caused a drop 

 ping of the foliage and a blackening of the more tender growth, 

 yet the plants are not materially injured and will undoubtedly 

 put forth fresh shoots and foliage. But a single treatment has 

 been effectual in killing every individual scale. 



In connection with the hibernation of the species mentioned I 

 have been led to go over my own earlier records on the hibernat 

 ing habits of the family, as also over the records of the Division 

 of Entomology. I have compiled the facts contained in Prof. 

 Comstock's article in his own report as U. S. Entomologist for 

 1880. From these data it will appear that no general rule can 

 be formulated, and that we not only have species in the same sub 

 family hibernating either as larvae or in stages intermediate be 

 tween the larva and adult, but in the adult female form and in 

 the egg, and that some species will be found in all these different 

 stages of development during the winter. The fact remains, 

 however, that in the armored scales the great majority, in more 

 northern latitudes, hibernate in the egg state. 



SUMMARY OF RECORDS. 



Diaspinae. Arfidt'o/ttsobsc/trusComst. On Quercusphellos. The notes 

 indicate that in the District of Columbia this, species hibernates in both 

 the larva and adult states. No eggs have been observed. 



Aspidiotus tenebricosus Comst. Maples ; D. C. Viviparous; hiber 

 nates as adult female. 



Aspidiotus perniciostis Comst. On Apple and a number of other 

 deciduous fruit trees; California. Specimens examined in December, 

 1879, showed that the mature females were hibernating, and that with 

 some of them were found a few eggs and recently hatched larv*. There 



