62 



SIXTH ANNUAL REPORT 



The enemies known to attack the Phylloxera under-ground are,* 

 naturally enough, fewer in number. In one instance I have found a 

 Scyranus larva at the work six inches below the surface, and there is a 

 Syrphus fly {PipLia radicimi, W. & Ii.,Fig. 15), whose larva lives un- 

 der-ground and feeds both on the Apple-tree Root-louse, and on this 

 Grape lioot-louse. Wonderful indeed is the instinct which teaches this 

 blind larva to penetrate the soil in search of its prey ; for the egg must 

 necessarily be laid at the surface. But though the under-ground ene- 

 mies of its own class are few, I have discovered a mite which preys 

 ■extensively upon this root-inhabiting type, and which renders efficient 

 f^^^- ^^1 aid in keeping it in check in this 



country. "Y^hi^ -miie {T>/roglypJius 

 "fphylloxercGy Planchon & Riley,Fig. 

 16.) belongs to the same genus (17) 

 as the cheese and meal mites 

 {T. siro Zi7in.), and the species 

 (T. entomopliagu^ Laboulbene) 

 which infests preserved insects and 



Boot-louse Syrpiius-fly: o, laiva; b, pupa; c, fly. is SUCh a pest in CabinetS. As is 



the rule with mites, it is born with but six legs, but acquires eight 

 [^^"- 1'^ ] after the first or second molts. 



It varies considerably in form, 

 with age, and in studying it with 

 a view of distinguishing it specifi- 

 cally from other described spe- 

 cies, I have noticed all the differ- 

 ent tarsal characters shown as 

 6?, /", cf and h (Fig. 16), and on 

 which distinct genera have been 

 founded. Mites present them- 

 in such different forms 

 that the adolescent stages of the same species have been made to rep- 

 Tesent distinct families by authors who never studied the development 

 •of these beings. Thus the genera Astoma^ Leptus^ Caris^ Myohia^ 

 etc., are now known to be but the larval forms, some of them com- 

 monly met with as such but not yet connected with the more perfect 

 and mature forms. The different species of Tyroglyphus^ so far known, 

 prey on vegetal and animal substances, particularly when these are in 

 a decaying or putrescent condition. In one of their forms {Ilypopus) 

 they are also known to be externally parasitic on living animals. 

 The species under consideration combines both habits, as when young 

 it mostly contents itself with the altered sweets of the roots which 

 rot from the punctures of Phylloxera, while when older it prej'-s by 

 preference on the lice themselves. 



^Phylloxera Mite : a, dorsnl; b, ventral view of fe- 

 male; c, mouth-piirts ; (l,f, g, h, forms of tav.sal i 

 ftppeudiiges ;(', ventral tubercles of male. SeiVeS 



