268 [October, 



mens much swollen the integument becomes almost transparent. It 

 is somewhat exceptional for the perfected parasites to escape througli 

 the dermis by making and leaving the usual perforations, they more 

 frequently leave the body of their host through the anal cleft, as there 

 is no other means of escape if they have not made such for them- 

 selves. When this is the case, they appear to have completed their 

 metamorphoses below the ventral skin of the host, thus the scale 

 remains apparently intact, and one can easily see how such specimens 

 would pass for perfect ; they, however, have had the whole interior 

 eaten away, but when the parasites escape through the dermis, the 

 ventral surface generally remains entire. 



At present I am unable to single out this parasite fi-om other 

 species which appear at the same time ; this, however, could be easily 

 accomplished by keeping the scales isolated. Por the time being the 

 foregoing is sufficient to show that the greatest care should be exercised 

 to select unparasitized specimens for description ; for while some 

 parasites may not materially affect the exterior of the scale, they are 

 quite capable of malforming the antennae and legs, especially such 

 species as feed upon the larvse and ova when in the scale. 



Grosvenor Museum, Chester : 

 July 28th, 1891. 



EEMAEKS ON THE ALTERATION OF THE AERIAL HABITS OF 

 CERTAIN GALL-FORMING APHIDES. 



BY G. B. BUCKTON, F.R.S. 



Though there is nothing new in the record of subterranean forms 

 obtaining in many genera of Ajjliides, there may be some interest felt 

 in the following note. Subterranean habits have been observed in 

 the genera Siphonophora, Aphis, Pemphigus, Schizoneura, Paracletus, 

 and Trama. In plate cxii of the " Monograph of British Aphides," 

 may be seen figures of Pemphigus lactucarius, and also a section of a 

 clod of earth, exposing a cavity containing numerous immature forms 

 of the same insect. 



Again, in plate cxiii, figures may be seen of the bottle-like purses 

 made by Pemphigus hursarius. M. Jules Lichtenstein, as is well 

 known, bestowed much attention upon Homopterous insects, and he 

 assumed that the great part of the Pemphigince and Phylloxerince, in 

 their second phase of development, were W'inged, and that in this con- 

 dition they migrated from the ordinary food-plant to form hibernating 

 colonies. His observations suggested to him the name " Pseudogyna 

 migrans,'' for an expression of this condition of their development. 



