338 



ENTOMOLOGICAL NEWS 



fNov.,'i8 



Legs 



Tarsus I 



Tarsi I and II 



Tarsus IV. 



Male. 



Bristles of female. 



Tarsus of hypopus 



Suctorial plate of hypo 

 pus 



R. sagittatae. 



short stout 



broader than long 



with one stiff bristle ; 

 with five elliptic spine 

 plates 



two and one-half times 

 as long as broad ; four 

 spined,noapical hairs 



heteromorphic, leg III 

 thickened ; terminal 

 spine not sickle-sha- 

 ped ; one large and 

 two elliptic fiat spine 

 plates 



six dorsal abdominal 

 near tip, two ventral 

 abdominal postanal 



R. hyacinthi. 



R. rhizophagris 



short, stout 



longer than broad 



with two bristles ; with 

 four acutely pointed 

 short spines 



three times as long as 

 broad; three spined. 

 two apical hairs 



heteromorphic, leg III 

 thickened; terminal 

 spine sickle-shaped 



: short, stout 



I longer than broad 



with two bristles ; with 

 five acutely pointed 

 short spines 



three times as long as 

 broad; three spined, 

 two apical hairs 



homomorphic, leg III 

 not thickened, termi" 

 nal spine sickle-sha- 

 ped 



terminated 

 claw 



by 



two inner rows of three 

 suckers, two outer 

 rows of one sucker, 

 one pair anterior to 

 plate 



six dorsal abdominal 

 near tip, four sub- 

 equal ventral abdo- 

 minal 



: terminated by stout sin- 

 I gle claw 

 1 

 two longitudinal row'S 



of three suckers, me- 

 dian one largest, one 

 outer row of one suc- 

 ker, four corner suc- 



ers 



eight doisal abdominal 

 near tip, four sub- 

 equal ventral abdo- 

 minal 



The various species of the genus RKxzoglyphus are noted for 

 their root- or bulb-eating propensity. The cosmopoHtan 

 sjiecies, R. hyac'm\hi, is a serious pest to a great number of 

 cultivated bulbs (Michael 1903). It was at first thought that 

 this mite was merely a saprophyte or at most a parasite of 

 pathological tissues. But the recurrent finding of the creature 

 in otherwise healthy bulbs has caused the acarologist to dis- 

 card that view and to consider it as a primary parasite. R. 

 sagittatae is not a parasite of the root or underground stem 

 of Balsamorrliica sagitfata. It is, on the contrary, always 

 above ground, securing its nourishment from the aerial por- 

 tion of the plant at the season when the leaves are succulent 

 and juicy. It was even found on young seedlings some 

 twenty to forty days old, taken from the field. R. sagittatae is 



