HARDWICKE'S SCIENCE-GOSSIP. 



181 



stand what very powerful aids to progression these 

 organs must be. The left front leg of a species of 

 Atax shows the swimming thorns, and in Fig. 114 

 we have a portion much magnified ; the lower thorn 

 is bent out of place, the other two are in position. 



These mites have soft bodies, and long legs. The 

 bodies vary in shape in the different species. They 

 swim in a very peculiar manner, making a few 

 energetic strokes, and then resting with outstretched 

 legs until they gradually sink for some distance, 

 sometimes to the bottom of the vessel in which they 

 are kept ; when they walk, the fore legs are kept 

 stretched out in front, like antennae, and not used for 

 progression. The palpi have on the outer side of the 

 last joint but one, a large process, and on the inner 

 side, two smaller ones, so that in extreme flexion, the 

 last joint would have the one process on the outside, 



Fig. 118. — Atax. 2 inch objective. 



and the two smaller ones on the inner side, and 

 hence give the creature a powerful grip of anything 

 capable of being seized by them ; the figure shows 

 the outer side of the upper mandible, and the inner 

 side of the lower one ; the processes mentioned are 

 well shown, they are not, however, so well developed 

 in all species of Atax, the eyes are very curious, and 

 can be moved by powerful muscles ; each eye has two 

 lenses, one in front, and the other at the side, as in 

 some species of Trombiclium. The termination of 

 the body, and the arrangement of the sexual discs, or 

 cups, is very variable. I have very generally found 

 it difficult to make any specimens agree with those 

 figured by Koch. Fig. 118 represents an Atax, under 

 a two-inch objective, it resembles Koch's Atax 

 elegatis. The Y-shaped mark is yellow, the cceca 

 black, and the legs green ; the eyes are a dark 

 cinnabar red. 



THE COMMON ORCHIS {ORCHIS 

 MASCULA). 



MR. MALAN, in his paper on this subject, falls 

 into some errors with respect to the fertilisa- 

 tion which, unless they are corrected, will be certain 

 to lead those who have not been able to obtain this 

 flower very much astray. I will endeavour to point 

 them out, and also make a few remarks on other por- 

 tions of his paper. On page 76 he says : " Directly the 

 rostellum is touched a viscid drop exudes, which sets 

 hard and fast like cement, and when the bee with- 

 draws its head a pollinia is firmly attached." He 

 very curiously gives this as a quotation from Mr. 

 Darwin. Instead of that, Mr. Darwin's description is 

 as follows : "Let us suppose an insect to alight on 

 the labellum, which forms a good landing-place, and 

 to push its head into the chamber, in order 

 to reach with its proboscis the end of the 

 nectary. Owing to the pouch-formed ros- 

 tellum projecting into the gangway of the 

 nectary, it is scarcely possible that any 

 object can be pushed into it without the 

 rostellum being touched. The exterior 

 membrane of the rostellum then ruptures 

 in the proper lines, and the lip or pouch 

 is most easily depressed. When this is 

 effected the one or both of the viscid balls 

 will most infallibly touch the intruding 

 body, and whatever they touch they firmly 

 stick to." It will be noticed that this 

 quotation is very different from Mr. Malan's, 

 and I conclude he gave it from memory, 

 and in so doing has confounded the ferti- 

 lisation of Orchis mascida with that of 

 Listera ovata or Ncottia nidus-avis, both of 

 which explode ; and they are, I think, the 

 only English orchids which do so. 



Mr. Malan does not seem to have 

 noticed the lip or pouch which plays a 

 most important part in the fertilisation, 

 as it does, the viscid balls which are 

 to the base of the pollinia. Should the 

 pouch be depressed without the pollinia being re- 

 moved, it rises and protects the viscid balls ; or if 

 only one be removed it rises and protects the other. 

 This, as will be seen, is most essential, as otherwise, 

 the viscid matter setting in about thirty seconds, the 

 pollen would be wasted. Again he says: "The 

 viscid disc drying causes the pollinia to sweep through 

 an angle of about ninety degrees." This, I venture 

 to say, is rather misleading. If the viscid disc as a 

 whole dried, the pollinia, as any one who will think 

 for one moment will see, would not go through any 

 movement of depression; but would remain in an 

 upright position. It is caused by the drying of a 

 small portion of the disc on the side nearest the 

 centre of the flower, on the opposite side to the 

 pouch. Mr. Malan says that in April the tubers are 



covering, 

 attached 



