HALF-AN-HOUR AT THE MICROSCOPE. 57 



Other examples of Caryophyllaceous seeds in the Naturalists' 

 Circular^ for May, 1868, p. 114, and, as space is an object, I must 

 refer those of our members who wish for further information to 

 that source for it. 



Spiracle, larva of Stag-beetle (PI. IV., Figs. 7 and 8.) — This 

 shde furnishes an interesting and beautiful example of Spiracle in a 

 large burrowing Coleopterous larva. The outer crescentic portion 

 is composed of two layers ; the network strongly resembles in 

 structure the principal coat of the testa in Rape seed (see Fig. 729, 

 p. 343, in Hassall's " Adulterations detected in Food and 

 Medicine"). I think this just serves as a framework to support a 

 membrane of extreme tenuity, through which the outer air com- 

 municates with that in the tracheae. The coarse, arborescent 

 structure behind (we are looking at the specimen from the out- 

 side, so that it would be more correct to say " within ") is no 

 doubt for support to the hexagonally reticulate framework. 



The central portion is much injured by the action of potash, 

 to destruction by which, and consequent shrinking, the zigzag 

 lines present in this specimen are due. It would be more 

 instructive if the specimens were differently placed on the slide ; 

 taking the head of the creature as pointing to the left, the outer 

 curve of the crescent should point to the right. I have (along 

 with some pupae) had several specimens of this larva brought to 

 me. It is a wonderfully big fleshy fellow, as long and as thick 

 as a man's middle finger, and therefore " very jolly " for dissection. 

 The whole subject of spiracles is one much in need of elucidation ; 

 comparatively little has been done at it systematically. The best 

 work, that by the late R. Beck, is locked up and lost to the 

 world, the family declining either to publish or to allow to be 

 published his careful and accurate observations and drawings on 

 the subject. They require to be studied in the living state, and 

 on fresh specimens as well as after preparation. 



Egg", Parasite of Ground Hornbill (PI. V.) — If memory 

 serves me rightly, it approximates most nearly in structure to 

 that of the egg of Docophorus^ the eggs of one species of which 

 may be readily found above the orbits, or round the ears of young 

 cocks in the coming spring. Perhaps L. H. will kindly send 

 round a specimen ; mine are all stowed away, and I don't at this 

 moment know where to put hands upon them. Surely, some of 

 our members, by a little exertion, would be able to procure and 

 send round specimens of the louse itself, properly named, which 

 lays these beautiful eggs, and so add to our knowledge on the 

 subject ; it must be readily met with on the bird. 



Cheyletus eruditus has by an unfortunate oversight had an 

 incorrect name attached to it. The specimens are really of a 



Journal of Microscopy and Natural Science. 

 New Series. Vol. III. 1890. 



