80 



In the following table are summarized the data concerning place on 

 surface of fruits where the specimens were found : 



Above. 



On side. 



Below. 



Aspidiotus ancylus 



forbesi 



perniciosus . 



camellice... 

 Chionaspis furfurus . '. . 

 Mytilaspis pomorum ... 



Per cent. 

 7.33 



Per cent. 

 0.38 



34.75 

 78.26 

 13.80 

 71.18 



3.56 

 "8." 62* 



Per cent. 

 92.28 

 100 

 61.69 



21.74 

 77.58 



From a consideration of these figures I am inclined to assert that 

 the distribution of scale insects on the surface of fruits depends on the 

 sensitiveness of the insects to meteorological influences. Those not 

 sensitive are Aspidiotus camellice, and especially Mytilaspis pomorum; 

 those very sensitive are Aspidiotus ancylus and A. forbesi; Aspidiotus 

 perniciosus is comparatively not sensitive. 



STAGE AND SEX OF THE SCALE INSECTS (COUNTED ON FRUIT). 



Free living larvae have never been found, and the specimens desig- 

 nated as larvae are specimens already fixed. 



A. ancylus. — Among 262 specimens were 250 immature females, 12 

 larvae. There is therefore hardly any danger that this species could 

 be imported, although it is by far the most common species. 



A. forbesi. — Of the 17 specimens all were immature females, but in a 

 few instances (not enumerated here) a few male larvae were seen. On 

 account of the rarity and sensitiveness of this species there seems to 

 be no danger of its being imported. 



A. perniciosus. — I counted 82 males, 354 females, 259 larvae. The 

 specimens designated as males were, almost without exception, male 

 larvae or male pupae. Most of the females were almost mature and 

 many had eggs, but only 2 had mature embryos. The danger of impor- 

 tation of this species is therefore very great. In sendings of apples 

 (pears are sent to Germany only in a dried condition) which arrive in 

 the late fall of the year this danger is reduced to a minimum, but it 

 increases with the beginning of spring, reaching its maximum from 

 March to May. 



A. camellia\ — Of 33 specimens 1 was a male (dead), 10 females with 

 mature embryos, 12 females mature but without embryos, 9 young 

 females, and 1 larva. There is danger in its importation, since it 

 occurs only in warmer countries and since its home is southern Europe. 



Chionaspis furfurus. — Of 133 specimens 115 were females, 17 more or 

 less developed males, and 1 larva. Of the females 94 were filled with 

 eggs. The danger of the importation of this species appears to be 

 quite considerable, but is reduced by the facts that the species is con- 

 fined to warmer countries and that it is everywhere driven out by M. 

 pomorum, which is so common in Germany. 



