286 



INJURIOUS INSECTS AND FUNGI. 



[Dec. 1896. 



On account of the inactive state of the fungus and the general 

 decay of the bulbs, it cannot be decisively affirmed that this 

 disorder is altogether caused by Polyactis galanthina, or even by 

 any fungus especially, as in many of the bulbs, and particularly 

 on those least decayed, quantities of mites were found feeding 

 upon them, within their folds as well as immediately under the 

 dried skin. Mites in all stages of growth, and eggs, could be seen 

 within the hollows scooped out in the bulbs, and it must be 

 inferred that if they were not the main cause of the malady 

 affecting the snowdrops, they were contributory to it in no small 

 degree. 



Fig. 1 



Rhizoglyplins (galanthi ?), much magnified. 



This mite (Fig. 1) can just be detected without a glass. 

 The body is yellowish in colour, while the head and claws are of 

 a reddish shade. It has four pairs of feet in the perfect state, 

 but the larva has only three pairs. In the female the third pair 

 of feet are particulary thick, and this causes the fourth pair to 

 be pushed farther back than in the case of the male. This 

 peculiarity, according to Claparede, indicates that this mite is 

 a species of Rhizoglyphus, and distinguishes it from species 

 of the genus Tyroglyphus* 



There is no doubt whatever as to the mites feeding upon the 

 snowdrop bulbs, and upon the sound parts of them. They were 

 not following in the wake of the fungus, but were living upon 

 the juices of the bulb, and causing decay. On the other hand, 

 it cannot be affirmed that they alone occasioned the whole of 

 the mischief to the bulbs, nor can the amount of the harm due to 

 the fungus be determined. 



It seems to follow from the nature of this attack — whether due 

 mainly to the fungus Polyactis galanthina or to the Rhizo- 

 glyphus — that it is most desirable that ground upon which 

 diseased bulbs have been grown should not be planted again 

 until, at least, a year has elapsed, and it would be well to treat 

 such land with a dressing of very finely powdered gas lime. It 



* Studien an Acariden. Von Edouard Claparede. 



