1905.] 



The Bulb Mite. 



749 



infestation by the mite are : — Checking of the plants, the leaves 

 turning yellow ; failure to produce flowers ; and reddish-brown 

 spots on the scales of the bulb, indicating feeding places of the 

 pest. There has been some controversy as to whether the mites 

 are really the cause of the failure of the bulbs. Some maintain 

 that the decay of the bulb is due to error in treatment, e.g., in 

 eucharis bulbs to over-forcing, or bad drainage, or faults in 



Fig. i. 



Adult Male, magnified 95 times. (Both figures after A. D. Michael). 



temperature or moisture, or shade, and that the decaying bulbs 

 are then attacked by the mites. Michael, however, in many 

 experiments, has placed it beyond question that the mites attack 

 and, indeed prefer, sound bulbs, and the mites have been found 

 at their destructive work in otherwise good tulip bulbs. 



Description. — R. echinopus can be found in the stages of egg, 

 larva, nymph, hypopus, adult males of two forms, and female. 

 The adults have a smooth body, yellowish white in colour, 

 tinged with pink. The legs and rostrum are red. Each 

 mandible ends in a pair of pincers, the branches of the pincers 

 having three teeth. Just behind the second pair of legs on each 

 side of the body is a projecting hair. There are four pairs of 

 short thick legs, the two front pairs being the strongest; the legs 



