10 



FIRST ANNUAL REPORT OP 



represented at Figure 3, 3, to the motionless and memberless forms 

 shown at 5 and 6 of the same figure, is an evidence of the degenera- 

 tion or degradation in this insect as it approaches the imago state. 



Mr. Walsh, whose observations are recorded in his First Annual 

 Report, as Acting State Entomologist of Illinois, found nothing to in- 

 duce him to separate this insect from the old genus Aspidiotus in the 

 Bark-louse family, to which it had hitherto been referred. He also 

 showed that there were three distinct growths of the scale, differing 

 from each other in size and color, which he named respectively the 

 " larval scale" " medial scale" and " anal sack." ' He also inclined 

 to believe that both the "medial scale" and " anal sack" were formed 

 " by the anal surface of the original young larva being at two succes- 

 sive periods abnormally dilated and extended backwards, in the form 

 of a sack closed at tip ; and that, after this process is accomplished, 

 the insect always moults or sloughs off the whole of the external 

 scale." As to the formation of the " larval scale" he offers no expla- 

 nation. 



My own observations will be found in the " Report of the Com- 

 mittee on Entomology," published in the Transactions of the Illinois 

 State Horticultural Society for 1867 — pp. 109-112. Having had no op- 

 portunity of continuing them the past summer, and as they will con- 

 vey a good idea of this insect's mode of growth, I repeat them in part. 



[Fig- 3*.] 



The young lice usually leave the scales during the first week in 

 June. Prior to their hatching, the eggs which were previously snow- 

 white, become yellowish, and if the weather turn cool, immediately 

 after hatching, they will remain for two or three days under the scales 

 before dispersing over the tree. The following notes as before stated, 

 were made in Cook County, Illinois. 



June 6th. — Most of the eggs are hatched, but the young have not 

 yet left the scales. 



*These figures are highly magnified, the hair lines at their sides approximating the natural 

 lengths. 1, egg — natural size scarcely .01. 2, larva, as it appears when running over the twigs — 

 natural length .01. 3, its appearance soon after becoming fixed. 4, appearance of scale after the 

 second plate is formed. 5, form of louse (ventral view) soon after losing jts members. 6, form of 

 louse (ventral view) when full grown and just about to deposit. 7, fully formed scale, containing 

 louse, as it appears from the underside, when raised. 8, highly magnified antenna of larva, show- 

 ing joints. 



